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Two new band systems of the spectrum of IrC in the region 6600–8500 Å
.TOURNAL
OF
MOLECULAR
Two
36, 248-267 (1970)
SPECTROSCOPY
New
Band
Systems
of the Spectrum
in the Region I
i
AND ROSE~IARY SCULL~IAN
JANSSON
of Physics,
6600-8500
of IrC
liniversify
of Stockholm,
Stockholm,
Sweden
Two new systeps belonging to the spectrum of IrC situated in the spectral
region 6600-8500 A have been rotationally analyzed. These systems have been designated D W-X 2Aand E ZA-X 2A.The ground X 2Astate is found to be iden-
tical with the lower state of two earlier reported systems in the region 48005300 ,&. The X 2Astate is inverted and has a strong spin-orbit interaction. The following value of the equilibrium internuclear distance for this state was obtained: rg = 1.683 .f\. INTRODUCTION The spectrum of IrC was first reported bx Jansson et al. (1). They found foul red-shaded bands in the region 4SOO-5300 A. These four bands originated from two syst.ems with the same lower &ate. The bands mere assumed to be the 2~p;i~-2A~~~ and the 2113ia-2As,zsubbands of a 2+-2A and a 21%-2Atransition. However, it, was not excluded that the kansit,ions might be 2r-2% and 2A-29. The investigation has now been extended both to shorter and t,o longer wav,elengths. No bands originating fro? IrC were detected in t,he region 26003800 A. However, between 5300 and 8500 A, many new bands belonging to IrC have been found. Ten of these bands have been rotat.ionally analyzed, Their band heads are given in Table I. The bands belong t’o two new systems with the same lower state as the systems earlier analyzed. The new systems are here called the D2+X2A and the E2A-X2A systems. The reason why the systems are designated in this way is given in the Discussion
below. The analysis
st,a,te is invert,ed and has a large coupling the analyzed levels is given in Fig. 1. EXPERIMENTAL The IrC molecule
was produced
constant.
showed that the X2A
An energy
level diagram
of
METHOIB
in a King furnace
in the same way as earlier
reported for the carbides PtC (2) and RhC (3). The argon at a pressure of 400 Torr at room temperature.
furnace About
was filled w&h 1 g of iridium
powder in a graphite vessel was heated electrically in a graphite tube to about 3000°C. The absorption speckurn was photographed between 2600 and 4800 A 248
SPECTRUM
OF IrC
TABLE
249
I
BAND HEADS AND ORIGINS
Band
Band head [A 641
Band head (cm-‘)
E*A~~~-X*A~~~
O-o l-l 2-2
6612.1 6655.8 6701.0
15 119.71 15 020.42 14 918.99
E2A31z-XZA31z
o-o l-l 2-2 3-3
8217.1 8273.9 8332.7 8393.1
12 12 11 11
166.41 082.92 997.64 911.26
12 145.3 zk 0.1 12 064 f 1
1-O 2-l 04 l-l 2-2 o-1 l-2
6540.5 6600 6960.4 7022.9 7087.9 7509.1 7576.6
15 15 14 14 14 13 13
285.2 147 362.97 235.16 104.54 313.45 194.76
15 277.5
f
0.4
14 353.84 14 226.49 14 096.28
f f f
0.04 0.04 0.08
Systems
Dl,,zx=A~/~
Origin (cm-‘) 15 100.81 f 15 002.7 f 14 902.8 f
13 184.5 f
0.04 0.1 0.2
0.4
b D2 *7,2
N 3200 -._I.-.-; x2A3,2
42
L
1051
4 X2A5,2
FIG. 1. Energy level diagram with wave numbers of the band heads. Not rotationally analyzed bands and levels are drawn with a broken line.
but no IrC bands were found in this region. However, the absorp$ion as well as the emission spectrum was photographed between 5300 and 8500 A. The absorption spectrum was produced using an intense source of continuous light, viz., a high pressure xenon lamp, Osram XBO 900 W.
250
JANSSON
AND
SCULLMAN
The spectrum was photographed in an Eagle spectrograph with a 10.68.5-m Bausch & Lomb concave grating with600 grooxes/mm and a ruled area of 100 X 198 mm’. The bands between 6600 and 7100 A were photographed in a second order where the linear dispersion amounted to approximately I..5 mm A-‘. An exposure time of about 3 min was needed using Kodak 10%F and Kodak 1-K plates. The bands at, longer wavelengths were photographed in a first order. In this case, an exposure time of 20 min n-as needed using Kodak 1-N plates. This was partly due to the weakness of the bands and part,ly due to the blaze wavelength of the grating (11 500 A) which also makes an intensity comparison of the bands in different parts of the speckurn difficult. However, such a comparison between the E ‘AS/~-X 2As,8 and the E 2Aa,s-X ‘Ax/n subbands is of great interest. Therefore, these bands were also photographed in another Eagle spectrograph Gth a 6.655-m Bausch & Ilomb concave grating with 1‘200 grooves/mm, :t ruled area of 100 X 175 mm2 and a blaze wavelengt’h at, 7.500 A. Since only the most intense bands have appeared in absorption, we have preferred to measure the emission bands. Lines from an iron arc were used for reference. Their ~vavrlengths were taken from the JIIT tables. The bands were measured in an Abbe comparator. The wave numbers were determined from t,hese comparator readings using a computer program written by Edvinsson ef al. (4). The lines of the bands are given in Table: II, III, and IV after the text. The lines of t hc bands between 4800 and 3300 A reported earlier have not been published before and use of them has been made in this paper. These IineF are therefore also given and can be found in Tables IV and V. In Tables II, IV, and V, mass labels have been attached to the branches of bands showing isotope splitting. DESCRIPTION
OF THE
BANlX3
‘lh bands of IrC hitherto detected are all red-shaded. Of the two systems described here only the 2%i/2-4A5/2 subbands of the I1 %-X 2A system were deiected. However, of the E ‘A-X 2A system, we found not only the 2A6,r-2A5j2 subbands but also the ‘Az,~-~As~? subbands despite the fact that, the 2Aajs-sAa,r subbands are much weaker than thr 2A5!y-2A &I2subbands. A spectrogram of the O-O band of the D %7,2-X *A.~,zsystem and of the 04 band of the E 2A5~2-X’Arjr system is given in Fig. 2.
The O-O, 14, and O-l sequences of the D %7,2-X 2Aj~ transition have been detected. The O-O, l-l, 2-3, l-2, and l-0 bands of these sequences were rotationally analyzed but only t’he band heads of the 2-1 and O-l bands were measured. The bands consist) of one R branch, one Q branch and one P branch. Since the P branch is considerably weaker than the R and Q branches, we were not able t
--..,
FIG. 2. Spectrograms transitiorl.
of the O-O band of the
D 3 ~/z--Ti Zaire transition
and of the O-O band of the E 2Ajj2 -S
2A6j2
N 01 w
JANSSON AND SCULLMAN
2.-,L’
.I numbers the R lines are even more intense than the Q lines. This made it possible for us to discover the R line which has the lowest, J number. The lines of the O-0 band show at high J numbers a rotational isotope splitting which was det.ect.able as two separated lines from J = 78>$ in the P branch and from J = 94% in the Q branch. The 14, O-l and l-2 bands also show a vibrational isotope splitting. The isotope splittings are of a magnitude expected for IrC. The relative intensities of t,he isotopic lines correspond well with the natural abundances 35.5 and 61.5 % of the isotopes “‘Ir and lg31r. The l-1 band is a rather strong band and all three branches were detected, whereas only the R and Q branches could be found in the 2-2 band. The 1-O band, which is rather weak, is heavily overlapped by other IrC bands. For this reason we only picked out a Q branch of this band. The isotope splitting of course reduces t,he apparent, intensity of this band. The 2-I , G1 and 1-2 bands are weak for the same reason. However, we made great efforts to find lines belonging to the l-2 band because they gave information about the v” = 2 level of X ‘As/n. The analysis of this level made it easier to analyze the v’ = 2 level of D 2@7,r from the weak 2-3 band which is overlapped by several other bands. ?‘Ile fl “A--k’ ‘0 Syste?rl
III th ,!?‘A-x’ 2A system, only the t.wo O-0 sequences were found. However, ttlis is not surprising, since the R values of the lower and upper states do not differ much. This is also the reason why isotope splitting has not been detected in this system, since lines of high .J are then situated rat,her close t.o the origin. Thr 6 ‘A~-ri ‘A312bands are much weaker than t,he E 2A6,2-ly*As,* bands but fortunately the former are situated in a region free from other bands. We were therefore able to analyze not only the 04 and l-l bands of the 2A5,2-2As,stransition butf also the 0-O and l-l one R branch
and one P branch
bands
of the 2Ap,2-2A3,2 transition.
of the same intensity.
The bands
have
No Q lines were detected.
Our knowledge of the uN = 2 level of X2A5,? made an analysis possible of the heavily overlapped S-2 band of the ‘As,~-‘A 5,2 tjransition. Because of the clean background, the band heads of the 2-2 and 3-3 bands of the 2A3,2-2A3,2 transition could be measured, but the bands lvere too weak to be rotationally analyzed.
The analysis has shown that there is no A-type doubling in any level, neither in those of the D 2GX ‘A system nor in those of tbe E ‘A--Y “A system. Hund’s coupling case (a) applies both to the X 2A state and t,o the E ‘A state. The X 2A state is inverted and has a large spin-orbit coupling constant (A” :Z -11600 cm-~‘). This is probably the reason why the D &,,,-X “A,,, subbands were not drtccted. The spin-orbit interact.ion is further discussed in t.he next section.
SPECTRUM MOLECULAR
OF IrC
253
CONSTANTS
Rotational Constants The rotational constams B, and D, were determined graphically from the combination differences. Second combination differences were used except for the V’ = 2 level of D ‘@i/z where first combination differences were used. This was done because the 2-2 band of D 2+7,z-X ‘Abj2 is so weak and overlapped that the P branch could not be det’ected. As no sign of A-type doubling has been seen, no systematic error will be introduced thereby. These R, and D, values are given in Table VI together wit.11 their est.imat.ed errors. To obt,ain more accurate values of the B, and D, constants for the vn = 0 and vl) = 1 levels of the X ‘A~,u state, these were recalculated using the average of all AzF values. All B, and D, values were moreover calculated using the method of least squares. As expected this gave t,he same result. The standard errors are however about. two or three times loss than t,he estimated errors. Since the staCstica1 TABLE
VI
ROTATIONAL CONSTANTS (cm-l) State Constants
determined
0
D, X lo6
&
graphically
Ay2Aj,?
0 1 2
0.5252 0.5220 0.519
f 0.0001 f 0.0003 l 0.001
0.52 0.52
z!z 0.01 f. 0.06
x2Am
0 1
0.5255 0.5220
f f
0.0002 0.0005
0.55 0.55
f f
D%lZ
0 1 2
0.5034 f 0.4995 f 0.496 f
O.OOtJl 0.0005 0.001
0.59 0.6
zk 0.03 f 0.1
0 1 2
0.5112 0.5070 0.504
f f f
0.0001 0.0002 0.001
0.62 0.63
0 1
0.5127 0.5084
f *
0.0002 0.0005
0.59 0.54
E*A~/~
EZAs/2
Constants
obtained from
the formula
given by Almy and Horsfall B
-
-
0.02 0.08
zt 0.02 =I=0.03
f f
0.02 0.07
(6) D X lo6
XM
0
0.5253
0.53
EZA
0 1
0.5120 0.5078
0.61 0.61
“54
JANSSON
ANl)
KXJLI,MAN
ma.terial is rather small for t.he highest vibrational levels, give, in Table VI, t,he graphically determined values.
we have preferred
to
The origins v0 were calculated from t,he Q lines in the D-X system and from t.he R a,nd P lines in t.he E&k system. The foilowing polynoms were then assumed 10 he valid (5) :
Hoover, for the 14 band of the D-X system, a D term had t’o be added. The calculation was made graphically. The Y,,values are given in Table I togethel \vith their estimated errors. The vibrational constants wp and w,x,. for the S 2Aa,2, D ‘@T,? and E ‘Aa!:!atl:ittJs were calculated from these ~0values using t,lte formula: v,, = Y,.-
W,” (P” + 12 ) + WeNXefl (v” + f ‘j )’ + cd,’(v’ + 3; ) -
Tliese constants are given in Table VII. The vibrational constants S ‘Ay12 system could not be calculated as we have here only sequence.
cd,‘&’ (0’ + 1 2 )‘. for the fi 2A:j,2-m found the O-O
We hnve here assumed the bands at 6612.1 and S217.1 8 to be the Tao O-0 euhbands of a ‘A-‘A transition. The reasons for this assumption are developed below. The structures are very similar and the rotational constants arc nearly equal. The R, values differ less than an a! value. The relative posit’ion of these levels has so far not been established since no intercombining bands have been detectrd. However, if the assumpbion is true that, they are subbands of the same sgst,em, it. is very improbable that such an intercombining band will be found since such iransitions are forbidden according to the selection rules. On the other hand it should he possible to estimate the energy difference betn-een the sublevels b>
SPECTRUM fitting an energy formula to the term values. by Almy and Horsfall (6’-7) :
Td J) TudJ)
255
OF IrC The formula
chosen is the one given
=
T(x = 0) + (B + D)x - Dk [A -
2(B 4
2Dx)12A2
+ (B -
2Dx)‘s
112 ,
where x = (J + $$))” - A2. The t,erm values were calculated from second combination differences, since we have no first combination differences for the ‘A312states. This is also the reason why we used only every second t.erm value in the calculat,ion. The term values wit.h J - $,$Ias an even number in the lower states and wit.h J - $,$ as an odd number in the upper states were calculated from the 04 and l-l bands. The calculation was made in the following way. An A value was chosen as a fixed value. Then the other constants were changed until a best fit of the formula to the termOvalues was obtained. This was done by using a computer program written by Aslund (8) and adapted to the IBJ!l-360/75 computer by Rlynning. The computer not only gives the T, B, and D values for a best fit, but also the rms value of the differences between the observed and calculated term values for this fixed A value. The process is then repeat,ed for another fixed A value, and so on. A plot of the rms value as a function of A for the lowest vibrational levels of the X “A and E “A states is shown in Fig. 3. The plots show that the minimum is much more pronounced for the upper level than for the lower level (note t.he difference in scale). That A value which gives the minimum rms value is considered to be the best one obtainable from this calculation. The broad minimum for the lower state is of course due to t,he small difference of the Bo” values, i.e.,
FIG. 3. The rms error as a function of the spin-orbit coupling the II = 0 levels of the X 2A (left) and E zA (right) states.
constants
A” and S’
for
“.j6
JANSSON
AND
SCULLMAN
t,he difference between the term values for the X ‘AX/~and X ‘A6,2 levels changes very slowly with J. An A value could not, be calculated for the X “A (v” = 1) level since the two B1” values are approximately equal. The est,imation of the A values is based on a rabher small amount of experimental data, since only the most accurately det,ermined term values, which were about 30, could be used. The estimnt’ion is consequently very approximate. An at.tempt, was made to estimate t’he accuracy of the Ao’ value which seems t(o be the best determined A va,lue. For this purpose the term values were divided into t,n:o groups, one with low ,I numbers and the other with high J numbers. Separak calculations were then performed on the two groups. The -446values so determined differ by about 30%. This large difference may be due to t.he neglection of a J dependence in A. The result of t)he estimation of the spin-orbit, coupling constants, when using all the calculated term values, is: 4;
.2 - 1500 cm-.‘,
j4 0’ 2
-120
cm-‘,
At’ .z - 120 cm-l. The shift of the two 0-O subbands 2(A”
-
of the E *A-X ‘A system A’) :z -2800
t,hen becomes
cm-’
which seems to be in fairly good agreement with the observed shift (-2955 As the Ai value is cert,ainly more accurate than that, of At, a probably AoN value can be obtained from the observed shift and A,‘. This gives
cm-‘). better
A4 0” > - 1600 cm-l. This SON value has been used in Fig. 1. The B and D values obtainecl at best A values are given in Table VI. As expected t,hey are approximately equal t’o the average of the corresponding B, and D, values. The I~quiliDrium Internuclear Distcmce The equilibrium ing formula:
const,ant. B, for the X “A state was calculated B = B,, -
where B is taken as the mean value values were obtained:
from the follow-
a,(~ + s;),
of corresponding
B, = 0.5269 f
0.0004 cm-‘,
(Ye= 0.0034 f
0.0005 cm-‘.
B, values.
The following
SPECTRUM
From this B, value culated :
the equilibrium
2.57
OF IrC
internuclear
distance
for this st,at#e was cal-
re = 1.683 & 0.001 8. DISCUSSION
The Character of the Lowest State The analysis has shown that the earlier reported systems (1) and those analyzed here have the same lower state. The most intense bands of all these systems have been seen not only in emission but also in absorption. The lower state has thus been assumed to be the ground state. It has now been established that t,his state, here designated the X state, is a ‘A state. This is based upon some det’ected R and P lines at the lowest J numbers. From the spectrogram of the O-O band at 6960.4 A of the D-,X system (see Fig. 2) it can be seen that the first R line is R (2%). This confirms the assumpt.ion made earlier (1) that the lowest state has s2 = 5/2. A decision between a ‘A s/t and a ‘@G,~state could not be made without the other set. of subbands. However, the corresponding 2A3/“-2A3j2 subbands of the E-X system were observed in the region 8200-8400 A where fortunately there are no overlapping bands. This made it possible to detect some interesting R and P lines with low J numbers in the 04 band. The turning R branch partly overlaps the R lines with low J numbers. However, just, beside and on the short wave1engt.h side of the R (7455) line, a weak line could be seen. This line is probably R (2%). It could be neither explained as an atomic line nor explained as a line of a band belonging to another molecule. A very weak line has also been seen at the place where the P (2%) line is expected to be situat’ed. No certain trace of the R (1%) line has been seen. According to theory, P (25; ) and R (1% ) should have the same intensity (9). The absence of the R (1%) line might be due to blending with a strong atomic line. As R (2%) and P (2%) should not be present in t,he alternative 2+~,2-2@~,Z transition, we have drawn t,he conclusion t,hat these bands are a 2A3/s-zA3/2 transition. A superscript a in Table III indicates that these lines have been discussed in this section or that they are overlapped. The Designation
of the States
The Ah:s for the systems are readily obtained from the band structure, the number of branches and their relative intensities. The two excited st’ates analyzed here were thus found to be a % and a ‘A. They have here been called D 2@ and E 2A. The earlier reported 211 and 24j states have then been assigned the capitals K and L, respectively. This means that the states earlier designat,ed I 2A, II ‘II, and III ‘@J(1) are now designated X 2A, K 2JI, and L %., respectively. The capitals have not been taken in alphabetic order as the ones omitted have been reserved for states which may be observed later on. The existence of additional stable states is very probable since two st.rong bands, one at 1.5 S46 cm-’
JANSSON
258
AND
SCULLMAN
and the other at 16 504 cm-‘, have been detected. These two bands have not yet, been analyzed. Their structure is different from that of the analyzed bands. Since no vibrational isotope splitting can be seen, the conclusion can be drawn that they are probably O-0 bands.
The normal state of the Ir atom is a % state and that of the C atom a 3P state. These states of the separated atoms give the following molecular states according to Wigner and Witmer (10): % (Ir)
+ “P(C)
---f [x+(3), I;-, II(3),
A(3), @((a), I’]2*4’6.
The normal “F state of the Ir atom is partly overlapped by the first excited state, another 4F state: which is also partly overlapped by the next excited st.ate and so on up t.o a rather high energy level. The number of possible low-lying molecular st,at,es is therefore quite numerous. However, t,he normal atomic states are sufficient to explain the observed molecular states. IrC is a heavy molecule with its two constituents from different periods of the periodic table. Moreover the Ir atom is a transition element whose outer 5cl and 6s electrons are of nearly the same energy. Assuming that the 1s electrons of the C atom are not influenced by the molecule formation (11), we suggest the following electron configuration for the ground state: ---u$‘~~n~$
--+ ‘A2 .
This is slightly different, from the one given earlier (1) which was based on a comparison with PbH. Electron configurations for the excited 2@, “A, and ‘II states are also easily obtained by exciting one of the outer electrons. These configurat,ions also predict a considerable number of “3 and 2JJ states. The above mentioned unanalyzed bands have a st’ruct,ure typical for bands with Ab = 0. They may be transitions between these predicted B or II stat,es. Dissocialim Energy A rough estimation
of t’he dissociation D.=&
Adding the excitation energies limits relative to the minimum tained:
energy
can be made using t’he formula
we e
of the electronic of the potential
states, the following dissociation curve of the X 2A6/s state are ob-
D, (X ‘AS/~) = 62000 cK1, D, (D 2+~,2) = 51000 cm-‘, D, (E 2A5,2) = 58000 cm-‘.
SPECTRUM
259
OF IrC
These energy values should be compared with that given by McIntyre et a.1. (12). Using mass spectrometric techniques, they obtained the dissociation value Do0 = (14S.4 f 3.0) kcal/mole for IrC. In cm-’ this would be almost 52 000, which is in rather good agreement with the above values. However, the dissociation products may be different. This is very probable since the possible states in the Ir atom overlap each other due to a strong multiplet splitting. TahleII. Warenumbere for the lines of the O-O,
l-l
and
2-2 bands of
* the II 2P7,2 - X 2A5,2 systems.
2.5
R195(J) 14354.26 355.11
:$J)
P193(5)
;::
2:; 2: 9.5 10.5 11.5
12.5 13.5 14.5 15.5 16.5 17.5 18.5 19;5
20.5 21.5 22.5
228.54 229.28
360.35 360.80 361.21
31.5 32.5 33.5 34.5 35.5 36.5 37.5 38.5 39.5 40.5 41.5 42.5 43.5 44.5 45.5 46.5
232.34 232.83
347.76
233.27 233.66 234.01
361.57 361.90 362.19 ::z1
343.05
324.44
340.36 339.38 338.36
318.75 316.75 314.73 312.66
362179 362.90 362.96 362.97
333.79
329.91
299.27
361.20 360.76 360.27 359.78 359.20 358.58 357.92 357.23 356.48 355.70
328.53 327.10
296.89 294.47 291.99 289.49 286.91 204.32 281.69 279.01 276.27
354.86
312.27 310.40 308.48 306.52 304.51 302.45
362.19 361.95 361.60
:55:*:5 352:09 351.06 350.01
234.31 234.57 234.78 235.94 235.06 235.13
310.54 308.37 306.16
27.5
30.5
229.98 230.65 231.28 23l.82
358.08 356.72 359.31 359.85
23.5 24.5 25.5 26.5
28.5 29.5
R(J) 14226.90 227.75
14350.56
325.64 324.13 322.56 320.96 319.30 317.62 315.88 314.10
273.48 270.66
258.92 255.8s
2-2 ____~.
l-l
I
J
Q(J)
P(J)
R(J)
Q(J)
14104.52 104.42 104.27 104.07 103.83
14081.25 080.17
103.57 103.22 102.85 102.43
075.36 074.04 072.68 071.27
101.93 101.41 100.86 100.28
069.81 06'3.33 066.78 065.18
099.59 098.86 098.11
063.54 061.87 060.14
097.32 096.52 095.64
058.35 056.51
094.71 093.74 092.62
052.71
14223.06 222.89 222.67 222.44 222.12 221.75 221.33 220.87 220.37 219.82 219.23 218.57 217&k 217.13 216.34 215.52 214.65 213.71
14202.46 200.71 198.91 197.05 195.17 193.24 $91.29 189.29 187.24 185.15 183.0? 180.80
235.16 235.16 235.11 235.00 234.82 234.62
212.74 211.73 210.68
234.38 234.07 233.74 233.39
205.99 204.71 203.36 202.02
178.57 176.30
232.96 232.50 231.98 231.41 230.80 230.13 229.43 228.68
200.60
169.20
199.13 197.63 I96.06
227.87 227.03
187.59 185.75
166.74 164.25 161.70 159.08 156.47 153.78 151.03 148.25
226.14 225.20
183.88 181.96
224.23 223.20 222.12 220.98
179.97 177.97 175.90 173.80
209.57 208.42 207.23
194.45 192.80 191.11 139.38
173.99 171.62
145.43 142.56 139.64 136.70 133.69 130.63 127.57
091.54 090.45 089.24
079.03 077.86 076.64
054.64
050.75 048.73 046.68 044.54 042.313
“60
JANSSON
Table
II(coatinued)
-.
o-o
-___ J
-_ _ 47.5 40.5
R193(J)
Q'93(J)
P193(J)
348.91 347.76 346.56 345.32
300.35 298.21 296.02
252.77 249.64 246.40
293.77
243.23
51.5 52.5 53.5 54.5 55.5 56.5 57.5 58.5 59.5 60.5
344.01 342.67 341.29 339.85 338.36 336.84
291.50 289.17 286.80 264.38 281.93
239.97 236.67
:::*'6:
274.25 271.62 268.90
61.5 62.5
328.53 326.69
63.5 64.5 65.5 66.5 67.5 60.5
324.84 322.93 320.96 318.96
49.5 50.5
69.5 70.5
AND SCULLMAN
331:9e 330.28
316.95 314.82 312.67 310.50 308.25
71.5 72.5 73.5 74.5
305.96 303.62 301.23
;z';
298.79 296.30
7715 78.5 79.5 80.5
293.76 291.17 288.53 285.84
El.5 82.5
283.12 280.32
83.5 84.5 85.5 86.5 87.5 88.5
277.41 274.59 271.62 268.64 265.62 262.53
89.5 90.5
259.38 256.18
91.5 92.5 93.5
252.92
279.41 276.86
266.15 263.37 260.53 257.64 254.71 251.74 248.71
233.29 229.07 226.44 222.93 219.40 215,83 212.20
Q(J)
219.81
171.64
218.59 217.31 216.01
169.44 167.20 164.90
214.65 213.23 211.77 210.28 208.72
162.55 160.16
207.13 205.48 203.79
P(J) 124.44 121.20
j R(J) I
165.04 160.82
229.57 226.20 222.81
156.54 152.21
040.18 037.97
117.95 114.65 111.31 108.04
157.73 155.24 152.71 150.13 147.50
147.84 143.44 138.96 134.50 129.92 125.30
201.38
120.65
197.63 193.84 190.00 186.11 182.17
115.95 111.20
Q(J)
086.74
197.23 193.36 1~9.46 185.51 181.51
236.15 232.89
---
088.02
204.80 201.03
239.37
219.38 215.85 212.31 208.72 205.08
R(J)
2-2
!
l-l
208.53
177.46 173.38 169.23
245.64 242.52
I j
106.39
178.17 174.15 170.08
*Mass l-be1 indicates that the branch shows isotope splitting.
SPECTRUM
TableIn.
Wsrenumbsra
for the
*A J __k”-o 1.5 2.5 3.5 4.5 2:: 7.5
R(J)
141.54a
150.73* 151.6P
140.39a 139.22 138.02 136.82
152.46'
11.5
156.31
12.5
157.03 157.71 158.39 159.00 159.61 160.19
17.5 18.5 19.5 ?0.5 21.5 22.5 23.5 24.5 25.5 26.5 27.5 28.5 29.5 30.5 31.5 32.5 33.5 34.5 :z*: 37:s 38.5 39.5 40.5 41.5 42.5 43.5 44.5 45.5 46.5 47.5 48.5 %ee
P(J)
149.82a
10.5
13.5 14.5 15.5 16.5
- *A
J/2
linea
of
261
I&
the O-O and l-l
of
*As/2
- *Q2 l-l
o-o
l-l
R(J)
banda
X :A suetem.
P(J)
R(J)
P(J)
R(J)
P(J)
12147.94a 14t~89~12142.64~
153.29a 154.09a 154.87 155.60
;:;
3/*
the
E *A-
OF
135.58 134.34 133.34
15110.93 111,61 112.28 112.92
131.71 130.36 128.99 127.63 126.20
113.52 114.10 114.66
124.76 123.29
160.73 161.23 161.72
121.81 120.27 118;7&
162.20 162.64 163.06 163.46 763.84 164.19 164.51 764.81 165.08
117.20 115.61
115.17 115.68 116.13 116.55 116.97
11j;9t3 112.34 110.66
117.34 117.70 118.02 118.31
108.97 107.23 1oj.4e
118.57 118.80 119.00
165.32
103.70 101.93
119.17 119.31
165.53 165.72
100.10 098.25 096.34 094.45 092.53 090.57
119.42 119.51 119.57 119.60 119.63 119.60
086.59 084.58 082.53
119.53 119.44 119.32 119.18
:z:: 166:17 166.26 166.32 166.36 166.39 166.36 166.31 166.23 166.11 765.96 165.78 165.55 165.33 165.09
Discussion
oee. 60
000.46
07+.04 071.85 069.64
12082.09 081.85 081.59
11990.97 988.73 986.48
118.98 118.75 118.50 778.22 117.92 117.58
067.39 065.12
081.32 081.03
984.17 981.85
117.22 116.82
078.33 07C.22
15088.44
087.09 065.72 084.33 082.88 081.42 079.94 078.44 076.90 075.31 073.71 072.07 070.41 068.73 067.01 065.28 063.51 061.70 059.s7 058.02 056.13 054.22 052.28 050.29 048.30 046.28
14951.59
044.24 042.13 040.03 037.88
15020.38 020.32 020.23 020.11 019.96 019.78 019.58
035.71
019.34
936.53
033.50 031.24 029.00 026.69
019.07 Olf3.78 018.45 018.08 017.68
934.29 931.99 929.65 927.28 924.88
017.24 016.77 016.29
922.45 919.97 917.47
024.39 022.03 ._ 019.66 017.25
_
949.53 947.45 945.34 943.18 941.02 938.80
.JANBSON AND SCULLMAN
’
J /
R(J)
p(J~! ____j_
P(J:
[ R(J)
P(J)
1 R(J)
P(J)
49.5 50.5
164.82 164.52
062.83 060.52
080.71 080.33
979.52 977.17
116.39
014.82
115.93
012.33
015.74 015.18
914.95 912.41
51.5 52.5 53.5 54.5 55.5 56.6
164.19 163.83 163.44 163.03 162.59 162.11 161.62 161.06 160.51
058.18 055.82
079.93 079.52 079.07 078.60
974.80 972.38 969.93 967.44 964.99 962.46
115.43 114.90 114.35 113.78
009.83 007.30 004.75 002.14
014.52 013.89 013.22 012.50
909.79 907.15 904.50 901.83
113.11 112.49
14999.52
011.75 010.99 010.17
899.07 896.31
57.5 58.5 59.5 60.5 61.5 62.5 63.5 64.5 65.5 66.5 67.5 68.5 69.5 70.5 71.5 72.5 73.5 74.5 75.5 76.5 77.5 78.5 79.5 80.5 81.5 82.5 83.5 84.5 85.5 86.5 57.5 88.5 89.5 90.5 91.5 92.5 93.5 94.5 ;65*: 97:5 98.5
053.42 051.00 048.56 046.07
159.96
043.59 041.06 03E.52 035.92
159.32 158.69 158.08
033.33 030.69 028.04
157.38 156.62
025.34 022.65
155.86 155.07 154.29 153.40 152.54
019.90 017.12
078.07 077.57 076.99 076.39 075.78 075.17
959.89 957.31 954.71 952.06
074.49 073.79
::69*::
073.04 072.28
943:9J3 941.21
014.32 011.50 00~.65
071.45 070.61 069.74 068.86 067.92 066.98
938.51 935.68 932.84 929.97
151.63 150.69
005.77 oon.e9
066.02 065.01
921.20 918.23
149.73 148.75 147.76 146.70 145.61 144.52 143.36 142.21
11999.93 996.97 993.97 990.95 987.89 984.87
063.95 062.87
915.23 912.21
141.02
975.44 972.26 969.05
139.78 lT8.50 137.22 135.90
981.75 978.61
965.79 962.54
134.55 133.14 131.70 130.26
;:;*z 952:54 949.11
.
;~,'%
.,
111.79 111.06 110.31 109.51 108.70 107.84 106.96 106.05 105.09 104.10 103.07 102.01 100.93 099.80 098.64 E$E o94:96 093.63 092.29 090.92 089.50 088.08 086.60 085.05 083.49 oa1.e7 080.21 078.53 076.81 075.05 073.26
128.80
945.73
071.43 069.50
127.26 125.76
942.34 938.81
067.57 065.58
124.19 122.56 120.91
935.30 931.80 92'3.23
063.57 061.50
119.26 117.53 115,eo
924.64 920.99 917.33
359.39 057.22
996.87 994.19 991.48 988.74 985.96
009.31 008.40 007.47
983.15 980.30
006.49 005.50
977.42 974.51 971.58 968.63
004.47 003.39 002.25 001.09
965.63 962.56
14999.87 998.66
959.50 956.42 953.30 950.13 946.93 943.70 940.44 937.15 933.82 930.44 927.06 923.62 920.14 916.62 913.10 909.53 905.90 902.27 898.56 894.83 891.08 887.26 883.39 879.50 875.59 871.63 867.61 063.60
893.53 890.70 887.82 884.91 881.98 879.00 876.00 872.94 869.85 866.76 863.60
SPECTRUM
Table of
the
system
D 2E7,2
-
and
l-l
D 2*7/2
the
-
j J
IV.
(J)\
Wavenumbers
X 2A5,2 band
X 2A5/2
E 2A5/2
of
the
I-O
2-2
band
of
the
E
X 2A
, 2 systemft
K 2Tr3j2
-
x
263
thelines
the
the
l-2
Q193(J)
for
system, of
OF IrC
2A5/2
-
K
2q2
P(J)
R(J)
2.5 3.5 4.5 2:: !': 9:5 10.5 11.5 12.5
14914.29 914.82 915.33 915.82 916.27 916.68 917.06 917.40
13.5 14.5 15.5 16.5 17.5 Is.5 19.5 20.5
71.5 22.5 23.5 24.5 25.5 26.5 27.5
13170.29 169.31 160.31 167.27 166.20 165.10
28.5
917.70 917.98 918.23 918.43 918.60
l4006.12 084.66 003.14 081.63
060.07 870.46 876.06 875.14 073.48 871.73 07O.Ol 868.25 066.30
19028.52 028.41 028.25 028.04 027.77 027.46 027.09 026.67 026.21 025.68
29.5 30.5
:%:I.
31.5 32.5 33.5 34.5 ;;.; 15241.84 239.99 238.10 3715 236.15 3e.5 234.15 39.5 232.08 40.5
161.60 160.33 159.04 157.70 156.30 154.87 153.40 151.90 150.39 148.85
025.12 024.47 023.80 023.04 022.26 021.42 020.54 019.56 018.60 017.56
147.24 145.56
016.45 015.28
41.5 42.5
229.92 227.73
l-2
bands
2A 5/z - x
-
x
2A5/2
2-$/2
l-l
2-2
R(J)
and
Q(J)
P(J)
19018.02 017.84 017.61 017.35 017.02 017.65 016.21 015.77 015.26
19015.46 014.30 013.03 011.77 010.47 009.12 007.68 006.21 004.72
014.71 014.05 013.36 012.66 011.90 011.09 010.22 009.32 008.39 007.35
003.24 001.64
006.27 005.17 004.01 002.76 001.51 000.22 18998. a4
997.40 995.94 994.43 992.85 991.26 989.59 987.85 986.07 984.24 982.36 980.45 978.44 976.42
'?z6e 996:49 994.70 992.85 990.94 988.97 906.94 984.90 ;x:: $4; 973:e9 971.55 969.16 966.72 964.22 961.64 959.07 956.41 953.68 950.92 948.09 945.23 942.31 ;:c:: . 933.25 930.08
264
JANSSON
Table IV D 2+2
AND
SCULLMAN
(continued). - K 2A5,2
E 2A5,2 - K 2A5,2
K 2r
2-2
R(J)
J 43.5 44.5 45.5
225.50 223.20 220.85
46.5 47.5 40.5 49.5 50.5
218.43
51.5 52.5 53.5
205.65 202.94 200.17
54.5 55.5 56.5
197.35 194.48 191.56 188.59
,,-_
57.5 58.5 59.5
66.5
-i-T P-(J)
143.86 142.12 140.37
215.97 213.46 210.90 noe.jo
Q(J)
P(J)
014.05 012.77 011.43 010.08 008.60 007.11
969.99 967.74 965.43 963.06 960.65 958.18
926.91
005.57 003.96
955.67 953.02
906.79 903.08
002.28 000.54 lB998.78
950.44 947.74 944.97 942.23
899.48 695.98 892.32 ma.55 884.64 13130.68 076.76 872.70 868.76 864.68
185.57 182.49 179.33
984.72
61.5 62.5
982.49 980.19
63.5 64.5 65.5
977.83 975.39 972.91
indicates
that
Table V. kvenumbers
the
branch
2A
5/2 _ .----
R(J)
996.95 995.03 993.12 991.09 989.04 986.90
*Mass label
- x 3/2
shows
isotope
;:c:: 933:44 930.45 927.31 924.17 920.96 917.69 914.38 911.02
923.69 920.41 917.09 913.70 910.29
860.53 856.32 852.06 847.74
907.59
splitting.
for the lines of the O-O and 1-O bands
system and of the O-O band of the L 26
20819.54 820.16
::: 4.5
19236.44 236.28 236.08
2:;
235.53 235.83
19228.96
7.5 ;::
235.19 234.38 234.80
227.63 224.81 226.23
10.5
233.92
223.35
820.71 821.17 821.56 821.87 822.08 822.20 822.25
20815.46 014.97 814.38 813.73 '312.95 812.12 811.21
SPECTRUM
Table
OF IrC
V (oontinued).
.~-
K 27/*- x %,* o-o J
R(J)
11.5 12.5 13.5 14.5 15.5 16.5 17.5 18.5 19.5 20.5 21.5 22.5 23.5
1-o _ _~~_
Q(J)
P(J)
233.38
221.85 220.29 218.68 217.03 215.34 213.58 211.78 209.92 208.06 206.10
232.80 232.20 231.56 230.87 230.12 229.33 228.51 227.63 226.71
204.11 202.11 200.07 197.97 195.82 193.60 191.35
L 2M;/2 - x 2A5/2 ______o-o ___~~ ~-.~ --
Q”‘(J)
R lg3(J)
Q”‘(J) 810.23 809.11 007.92 806.65 005.20 803.81 802.29 800.66 798.95 797.14
20799.12 797.05
20059.61 058.56
822.20 822.07 821.85 821.55 821.14 820.64 820.07 819.40 8113.61 817.79 816.83 815.82 014.68 813.49 812.18 810.82 809.36 007.7% 806.14 804.40
795.25 793.25 791.18 :,"z*;," 784:44 782.01 779.52 776.90 774.19
774.59 771.63 768.61 765.51 762.30 759.02
802.57 800.66 798.63 796.53
771.41 768.54 765.58 762.51
;;:*i: 789:6g 787.21 704.67 782.01
::z 752:79 749.36
25.5 26.5 2’7.5 28.5 29.5 30.5
247.95 247.74 247.49 247.20 246.07 246.46
225.75 224.75 223.67 222.55 221.39 220.19 218.92 217.64 216.27 214.91
31.5 32.5 33.5 34.5 35.5 36.5 37.5 38.5 39.5 40.5
246.02 245.56 245.02 244.43 243.82 243.14 242.39 241.60 240.77 239.89
213.40 211.99 210.46 208.88 207.25 205.59 203.84 202.08 200.27 198.40
181.88 179.40 176.88 174.32 171.72 169.02 166.30 163.52 160.71 157.86
41.5 42.5 43.5 44.5 :2*: 47:5 48.5 49.5 50.5
238.99 238.02 236.97 235.88 234.76 233.59 232.34 231.04 229.70 228.32
196.46 194.47 192.48 190.41 188.29 186.12 183.89 ls1.64 179.31 176.93
154.95 152.01 148.98 145.94 142.83 139.67 136.46 133.21 129.90 126.54
020.34 017.88 015.40 012.87 010.29 007.64 004.94 002.17 19999.38 996.50
51.5 52.5 53.5 54.5 55.5
226.89 225.41 223.84 222.27 220.62
174.51 172.05 169.50 166.94 164.30
123.13 119.67 116.14 112.62 109.00
;;;*:t 907147 984.32 981.11
24.5
.-_
19240.12
265
189.04,
106.77 184.33
Z,'E 054:98 053.67 052.26 050.80 049.29 047.68
:;z*:; . 773.52 770.50 :z:*:i 760:88 757.51 754.01 750.45 746.78 743.03
Plg3(
J)
;;:*;z 790:40 787.99 785.49 782.91 780.23 777.45
::zi 748:57 744.92
:::'z .
741.19 737.34 733.40 729.39 725.30 721.10 716.82 712.49 700.03 703.47
738.57 734.79 730.91 726.95 722.90 718.75 714.53 710.21 705.79 701.27
698.83 694.11 689.29 684.36 679.37 674.27 669.09 663.82 658.46 653.00
696.66 691.95 687.16 682.27 677.30
647.44 641.80 636.13 630.30 624.38
JANSSON
266 Table
AND
SCULLMXN
V (continued).
VT
2 K
3/z
- *
2 d5/2
---.0-o
L “7,2 .___
1-O
- ’
‘* 5/2
o-o Qlg3(J)
P’93(
J)
Q(J)
P(J)
Q’93(J)
Rrq3(J)
;:4”;:
727.04 722.82 718.50 714.09 709.60
672.22 667.06 661.79 656.45 651.00
:;;*:z .
704.98 700.27 695.46 690.57 685.59 680.49 675.31 669.99 664.60 659.14
645.46 639.89 634.13 628.31 622.39 616.30 610.27 604.07 597.76 591.37
586.92 580.35 573.70 567.00 560.i6 553.21 546.13 539.04 531.80 524.48
653.58 647.00 642.13 636.33 630.35 624.27 618.09 611.83 605.43 598.98
584.87 578.31 571.62 564.83 557.92 550.94 543.88 536.71 529.42 522.01
517.07 509.53 501.94 ",z:: 478154 470.51 462.44 454.26 445.98
81.5 82.5 83.5 84.5 85.5 86.5 87.5 88.5 89.5 90.5
592.45 585.75 578.97
514.57 506.98 499.32 491.52 483.64 475.65 467.58 459.41 451.13 442.75
437.59 429.10 420.53 411.84 403.11 394.17 385.21 376.13 366.94 357.66
91.5 92.5 93.5 94.5
521.13 513.44 505.64 497.72 489.70 481.55 473.30
56.5 57.5 58.5 59.5
218.93 217.16 215.33 213.44 211.50
161.61 150.86 156.08 153.22 150.32
105.33 101.61 097.66 094.03 090.15
61.5 62.5 63.5 64.5 65.5 66.5 67.5 68.5 69.5 70.5
209.49 207.42 205.37 203.18 200.95 190.67
147.37 44.35 41.28 38.16 34.97 31.74 28.43 25.07 21.68 18.20
086.22 082.24 078.20 074.11 069.95 065.76 061.49 057.20 052.83 048.40
71.5 72.5 73.5 74.5
86.47 83.85
;z’: . 77.5 78.5 79.5 80.5
;x; 69170 166.79
114.68 111.09 107.47 103.75 099.98 096.16 092.27 ose.32
043.88 039.34 034.74 030.09 025.36 020.58 015.74
60.5
;z’: 97:5 98.5 s9.5 100.5 101.5 102.5 103.5 104.5
96.3+ 93.98 91.54 B9.04
81.18
78.42
971:12 967.63 964.10 960.52 956.86 953.14 949.34 ;:z;: .
:::*z 558:OZ 550.84 ::z*:: 526:70
--
618.37 612.27 606.08
:;z';: 448IOl
:;:*;;s 381:,2 371.92 362.60 353.16
348.27 338.76 329.18 319.50 309.71 299.79 289.81 297.72 269.52 259.19
439.35 430.58 421.70 412.70
343.60 333.98 324.23 314.34
248.77 238.25 227.62 216.90
:::'z: 416198 408.14
-.--
*
Mass
label
indicates
that
the
branch
shows
isotope
splitting.
SPECTRUM
OF IrC
267
ACRNOWLEDGMF,NT We thank Professor Albin Lagerqvist for his never failing willingness to discuss our work, for reading though this article and making a number of useful suggestions, and Dr. Lennart Klynning for advice concerning the computer calculations of the spin-orbit coupling constants. We also thank Mrs. Marianne Nordin for the drawings and Mr. Ants Paas for the spectrogram. RECEIVED:April 24, 1970 REFERENCES 1. K. JANSSON,R. SCULLMAN, ANDB. YTTERMO,Chem. Phys. Lett. 4, 188 (1969). R. H. NEUHAUS,R. SCULLMAN, ANDB. YTTERMO,2. Naturforsch. 2Oa, 162 (1965). 3. A. LAGERQVIST, H. NEUHAUS,ANDR. SCULLMAN, 2. Nat,urforsch. 20a, 751 (1965). 4. G. EDVINSSON,I. KOPP, B. LINDGREN,ANDN. ASLUND,Ark. Fys. 26,95 (1963). 6. R. S. MULLIKEN,Rev. Mod. Phys. 2, 60 (1930). 6. G. M. ALMY ANDR. B. HORSFALL,Phys. Rev. 61, 491 (1937). 7. L. KLYNNING,B. LINDGREN,AND N.&LUND, Ark. Fys. 30, 141 (1965). 8. N. ASLUND,Ark. Fys. 30, 377 (1965). 9. I. Kovbcs, “Rotational Structure in the Spectra of Diatomic Molecules,” p. 121. Adam Hilger, London, 1969. 10. E. WIGNERANDE. E. WITMER,2. Phys. 61,859 (1928). f 1. J. E. LENNARD-JONES, Trans. Faraday Sot. 26, 668 (1929). 12. N. S. MCINTYRE,A. V. AUWERA-MAHEIU,ANDJ. DROWART,Trans. Faraday Sot. 64, 3006 (1968).
OF
MOLECULAR
Two
36, 248-267 (1970)
SPECTROSCOPY
New
Band
Systems
of the Spectrum
in the Region I
i
AND ROSE~IARY SCULL~IAN
JANSSON
of Physics,
6600-8500
of IrC
liniversify
of Stockholm,
Stockholm,
Sweden
Two new systeps belonging to the spectrum of IrC situated in the spectral
region 6600-8500 A have been rotationally analyzed. These systems have been designated D W-X 2Aand E ZA-X 2A.The ground X 2Astate is found to be iden-
tical with the lower state of two earlier reported systems in the region 48005300 ,&. The X 2Astate is inverted and has a strong spin-orbit interaction. The following value of the equilibrium internuclear distance for this state was obtained: rg = 1.683 .f\. INTRODUCTION The spectrum of IrC was first reported bx Jansson et al. (1). They found foul red-shaded bands in the region 4SOO-5300 A. These four bands originated from two syst.ems with the same lower &ate. The bands mere assumed to be the 2~p;i~-2A~~~ and the 2113ia-2As,zsubbands of a 2+-2A and a 21%-2Atransition. However, it, was not excluded that the kansit,ions might be 2r-2% and 2A-29. The investigation has now been extended both to shorter and t,o longer wav,elengths. No bands originating fro? IrC were detected in t,he region 26003800 A. However, between 5300 and 8500 A, many new bands belonging to IrC have been found. Ten of these bands have been rotat.ionally analyzed, Their band heads are given in Table I. The bands belong t’o two new systems with the same lower state as the systems earlier analyzed. The new systems are here called the D2+X2A and the E2A-X2A systems. The reason why the systems are designated in this way is given in the Discussion
below. The analysis
st,a,te is invert,ed and has a large coupling the analyzed levels is given in Fig. 1. EXPERIMENTAL The IrC molecule
was produced
constant.
showed that the X2A
An energy
level diagram
of
METHOIB
in a King furnace
in the same way as earlier
reported for the carbides PtC (2) and RhC (3). The argon at a pressure of 400 Torr at room temperature.
furnace About
was filled w&h 1 g of iridium
powder in a graphite vessel was heated electrically in a graphite tube to about 3000°C. The absorption speckurn was photographed between 2600 and 4800 A 248
SPECTRUM
OF IrC
TABLE
249
I
BAND HEADS AND ORIGINS
Band
Band head [A 641
Band head (cm-‘)
E*A~~~-X*A~~~
O-o l-l 2-2
6612.1 6655.8 6701.0
15 119.71 15 020.42 14 918.99
E2A31z-XZA31z
o-o l-l 2-2 3-3
8217.1 8273.9 8332.7 8393.1
12 12 11 11
166.41 082.92 997.64 911.26
12 145.3 zk 0.1 12 064 f 1
1-O 2-l 04 l-l 2-2 o-1 l-2
6540.5 6600 6960.4 7022.9 7087.9 7509.1 7576.6
15 15 14 14 14 13 13
285.2 147 362.97 235.16 104.54 313.45 194.76
15 277.5
f
0.4
14 353.84 14 226.49 14 096.28
f f f
0.04 0.04 0.08
Systems
Dl,,zx=A~/~
Origin (cm-‘) 15 100.81 f 15 002.7 f 14 902.8 f
13 184.5 f
0.04 0.1 0.2
0.4
b D2 *7,2
N 3200 -._I.-.-; x2A3,2
42
L
1051
4 X2A5,2
FIG. 1. Energy level diagram with wave numbers of the band heads. Not rotationally analyzed bands and levels are drawn with a broken line.
but no IrC bands were found in this region. However, the absorp$ion as well as the emission spectrum was photographed between 5300 and 8500 A. The absorption spectrum was produced using an intense source of continuous light, viz., a high pressure xenon lamp, Osram XBO 900 W.
250
JANSSON
AND
SCULLMAN
The spectrum was photographed in an Eagle spectrograph with a 10.68.5-m Bausch & Lomb concave grating with600 grooxes/mm and a ruled area of 100 X 198 mm’. The bands between 6600 and 7100 A were photographed in a second order where the linear dispersion amounted to approximately I..5 mm A-‘. An exposure time of about 3 min was needed using Kodak 10%F and Kodak 1-K plates. The bands at, longer wavelengths were photographed in a first order. In this case, an exposure time of 20 min n-as needed using Kodak 1-N plates. This was partly due to the weakness of the bands and part,ly due to the blaze wavelength of the grating (11 500 A) which also makes an intensity comparison of the bands in different parts of the speckurn difficult. However, such a comparison between the E ‘AS/~-X 2As,8 and the E 2Aa,s-X ‘Ax/n subbands is of great interest. Therefore, these bands were also photographed in another Eagle spectrograph Gth a 6.655-m Bausch & Ilomb concave grating with 1‘200 grooves/mm, :t ruled area of 100 X 175 mm2 and a blaze wavelengt’h at, 7.500 A. Since only the most intense bands have appeared in absorption, we have preferred to measure the emission bands. Lines from an iron arc were used for reference. Their ~vavrlengths were taken from the JIIT tables. The bands were measured in an Abbe comparator. The wave numbers were determined from t,hese comparator readings using a computer program written by Edvinsson ef al. (4). The lines of the bands are given in Table: II, III, and IV after the text. The lines of t hc bands between 4800 and 3300 A reported earlier have not been published before and use of them has been made in this paper. These IineF are therefore also given and can be found in Tables IV and V. In Tables II, IV, and V, mass labels have been attached to the branches of bands showing isotope splitting. DESCRIPTION
OF THE
BANlX3
‘lh bands of IrC hitherto detected are all red-shaded. Of the two systems described here only the 2%i/2-4A5/2 subbands of the I1 %-X 2A system were deiected. However, of the E ‘A-X 2A system, we found not only the 2A6,r-2A5j2 subbands but also the ‘Az,~-~As~? subbands despite the fact that, the 2Aajs-sAa,r subbands are much weaker than thr 2A5!y-2A &I2subbands. A spectrogram of the O-O band of the D %7,2-X *A.~,zsystem and of the 04 band of the E 2A5~2-X’Arjr system is given in Fig. 2.
The O-O, 14, and O-l sequences of the D %7,2-X 2Aj~ transition have been detected. The O-O, l-l, 2-3, l-2, and l-0 bands of these sequences were rotationally analyzed but only t’he band heads of the 2-1 and O-l bands were measured. The bands consist) of one R branch, one Q branch and one P branch. Since the P branch is considerably weaker than the R and Q branches, we were not able t
--..,
FIG. 2. Spectrograms transitiorl.
of the O-O band of the
D 3 ~/z--Ti Zaire transition
and of the O-O band of the E 2Ajj2 -S
2A6j2
N 01 w
JANSSON AND SCULLMAN
2.-,L’
.I numbers the R lines are even more intense than the Q lines. This made it possible for us to discover the R line which has the lowest, J number. The lines of the O-0 band show at high J numbers a rotational isotope splitting which was det.ect.able as two separated lines from J = 78>$ in the P branch and from J = 94% in the Q branch. The 14, O-l and l-2 bands also show a vibrational isotope splitting. The isotope splittings are of a magnitude expected for IrC. The relative intensities of t,he isotopic lines correspond well with the natural abundances 35.5 and 61.5 % of the isotopes “‘Ir and lg31r. The l-1 band is a rather strong band and all three branches were detected, whereas only the R and Q branches could be found in the 2-2 band. The 1-O band, which is rather weak, is heavily overlapped by other IrC bands. For this reason we only picked out a Q branch of this band. The isotope splitting of course reduces t,he apparent, intensity of this band. The 2-I , G1 and 1-2 bands are weak for the same reason. However, we made great efforts to find lines belonging to the l-2 band because they gave information about the v” = 2 level of X ‘As/n. The analysis of this level made it easier to analyze the v’ = 2 level of D 2@7,r from the weak 2-3 band which is overlapped by several other bands. ?‘Ile fl “A--k’ ‘0 Syste?rl
III th ,!?‘A-x’ 2A system, only the t.wo O-0 sequences were found. However, ttlis is not surprising, since the R values of the lower and upper states do not differ much. This is also the reason why isotope splitting has not been detected in this system, since lines of high .J are then situated rat,her close t.o the origin. Thr 6 ‘A~-ri ‘A312bands are much weaker than t,he E 2A6,2-ly*As,* bands but fortunately the former are situated in a region free from other bands. We were therefore able to analyze not only the 04 and l-l bands of the 2A5,2-2As,stransition butf also the 0-O and l-l one R branch
and one P branch
bands
of the 2Ap,2-2A3,2 transition.
of the same intensity.
The bands
have
No Q lines were detected.
Our knowledge of the uN = 2 level of X2A5,? made an analysis possible of the heavily overlapped S-2 band of the ‘As,~-‘A 5,2 tjransition. Because of the clean background, the band heads of the 2-2 and 3-3 bands of the 2A3,2-2A3,2 transition could be measured, but the bands lvere too weak to be rotationally analyzed.
The analysis has shown that there is no A-type doubling in any level, neither in those of the D 2GX ‘A system nor in those of tbe E ‘A--Y “A system. Hund’s coupling case (a) applies both to the X 2A state and t,o the E ‘A state. The X 2A state is inverted and has a large spin-orbit coupling constant (A” :Z -11600 cm-~‘). This is probably the reason why the D &,,,-X “A,,, subbands were not drtccted. The spin-orbit interact.ion is further discussed in t.he next section.
SPECTRUM MOLECULAR
OF IrC
253
CONSTANTS
Rotational Constants The rotational constams B, and D, were determined graphically from the combination differences. Second combination differences were used except for the V’ = 2 level of D ‘@i/z where first combination differences were used. This was done because the 2-2 band of D 2+7,z-X ‘Abj2 is so weak and overlapped that the P branch could not be det’ected. As no sign of A-type doubling has been seen, no systematic error will be introduced thereby. These R, and D, values are given in Table VI together wit.11 their est.imat.ed errors. To obt,ain more accurate values of the B, and D, constants for the vn = 0 and vl) = 1 levels of the X ‘A~,u state, these were recalculated using the average of all AzF values. All B, and D, values were moreover calculated using the method of least squares. As expected this gave t,he same result. The standard errors are however about. two or three times loss than t,he estimated errors. Since the staCstica1 TABLE
VI
ROTATIONAL CONSTANTS (cm-l) State Constants
determined
0
D, X lo6
&
graphically
Ay2Aj,?
0 1 2
0.5252 0.5220 0.519
f 0.0001 f 0.0003 l 0.001
0.52 0.52
z!z 0.01 f. 0.06
x2Am
0 1
0.5255 0.5220
f f
0.0002 0.0005
0.55 0.55
f f
D%lZ
0 1 2
0.5034 f 0.4995 f 0.496 f
O.OOtJl 0.0005 0.001
0.59 0.6
zk 0.03 f 0.1
0 1 2
0.5112 0.5070 0.504
f f f
0.0001 0.0002 0.001
0.62 0.63
0 1
0.5127 0.5084
f *
0.0002 0.0005
0.59 0.54
E*A~/~
EZAs/2
Constants
obtained from
the formula
given by Almy and Horsfall B
-
-
0.02 0.08
zt 0.02 =I=0.03
f f
0.02 0.07
(6) D X lo6
XM
0
0.5253
0.53
EZA
0 1
0.5120 0.5078
0.61 0.61
“54
JANSSON
ANl)
KXJLI,MAN
ma.terial is rather small for t.he highest vibrational levels, give, in Table VI, t,he graphically determined values.
we have preferred
to
The origins v0 were calculated from t,he Q lines in the D-X system and from t.he R a,nd P lines in t.he E&k system. The foilowing polynoms were then assumed 10 he valid (5) :
Hoover, for the 14 band of the D-X system, a D term had t’o be added. The calculation was made graphically. The Y,,values are given in Table I togethel \vith their estimated errors. The vibrational constants wp and w,x,. for the S 2Aa,2, D ‘@T,? and E ‘Aa!:!atl:ittJs were calculated from these ~0values using t,lte formula: v,, = Y,.-
W,” (P” + 12 ) + WeNXefl (v” + f ‘j )’ + cd,’(v’ + 3; ) -
Tliese constants are given in Table VII. The vibrational constants S ‘Ay12 system could not be calculated as we have here only sequence.
cd,‘&’ (0’ + 1 2 )‘. for the fi 2A:j,2-m found the O-O
We hnve here assumed the bands at 6612.1 and S217.1 8 to be the Tao O-0 euhbands of a ‘A-‘A transition. The reasons for this assumption are developed below. The structures are very similar and the rotational constants arc nearly equal. The R, values differ less than an a! value. The relative posit’ion of these levels has so far not been established since no intercombining bands have been detectrd. However, if the assumpbion is true that, they are subbands of the same sgst,em, it. is very improbable that such an intercombining band will be found since such iransitions are forbidden according to the selection rules. On the other hand it should he possible to estimate the energy difference betn-een the sublevels b>
SPECTRUM fitting an energy formula to the term values. by Almy and Horsfall (6’-7) :
Td J) TudJ)
255
OF IrC The formula
chosen is the one given
=
T(x = 0) + (B + D)x - Dk [A -
2(B 4
2Dx)12A2
+ (B -
2Dx)‘s
112 ,
where x = (J + $$))” - A2. The t,erm values were calculated from second combination differences, since we have no first combination differences for the ‘A312states. This is also the reason why we used only every second t.erm value in the calculat,ion. The term values wit.h J - $,$Ias an even number in the lower states and wit.h J - $,$ as an odd number in the upper states were calculated from the 04 and l-l bands. The calculation was made in the following way. An A value was chosen as a fixed value. Then the other constants were changed until a best fit of the formula to the termOvalues was obtained. This was done by using a computer program written by Aslund (8) and adapted to the IBJ!l-360/75 computer by Rlynning. The computer not only gives the T, B, and D values for a best fit, but also the rms value of the differences between the observed and calculated term values for this fixed A value. The process is then repeat,ed for another fixed A value, and so on. A plot of the rms value as a function of A for the lowest vibrational levels of the X “A and E “A states is shown in Fig. 3. The plots show that the minimum is much more pronounced for the upper level than for the lower level (note t.he difference in scale). That A value which gives the minimum rms value is considered to be the best one obtainable from this calculation. The broad minimum for the lower state is of course due to t,he small difference of the Bo” values, i.e.,
FIG. 3. The rms error as a function of the spin-orbit coupling the II = 0 levels of the X 2A (left) and E zA (right) states.
constants
A” and S’
for
“.j6
JANSSON
AND
SCULLMAN
t,he difference between the term values for the X ‘AX/~and X ‘A6,2 levels changes very slowly with J. An A value could not, be calculated for the X “A (v” = 1) level since the two B1” values are approximately equal. The est,imation of the A values is based on a rabher small amount of experimental data, since only the most accurately det,ermined term values, which were about 30, could be used. The estimnt’ion is consequently very approximate. An at.tempt, was made to estimate t’he accuracy of the Ao’ value which seems t(o be the best determined A va,lue. For this purpose the term values were divided into t,n:o groups, one with low ,I numbers and the other with high J numbers. Separak calculations were then performed on the two groups. The -446values so determined differ by about 30%. This large difference may be due to t.he neglection of a J dependence in A. The result of t)he estimation of the spin-orbit, coupling constants, when using all the calculated term values, is: 4;
.2 - 1500 cm-.‘,
j4 0’ 2
-120
cm-‘,
At’ .z - 120 cm-l. The shift of the two 0-O subbands 2(A”
-
of the E *A-X ‘A system A’) :z -2800
t,hen becomes
cm-’
which seems to be in fairly good agreement with the observed shift (-2955 As the Ai value is cert,ainly more accurate than that, of At, a probably AoN value can be obtained from the observed shift and A,‘. This gives
cm-‘). better
A4 0” > - 1600 cm-l. This SON value has been used in Fig. 1. The B and D values obtainecl at best A values are given in Table VI. As expected t,hey are approximately equal t’o the average of the corresponding B, and D, values. The I~quiliDrium Internuclear Distcmce The equilibrium ing formula:
const,ant. B, for the X “A state was calculated B = B,, -
where B is taken as the mean value values were obtained:
from the follow-
a,(~ + s;),
of corresponding
B, = 0.5269 f
0.0004 cm-‘,
(Ye= 0.0034 f
0.0005 cm-‘.
B, values.
The following
SPECTRUM
From this B, value culated :
the equilibrium
2.57
OF IrC
internuclear
distance
for this st,at#e was cal-
re = 1.683 & 0.001 8. DISCUSSION
The Character of the Lowest State The analysis has shown that the earlier reported systems (1) and those analyzed here have the same lower state. The most intense bands of all these systems have been seen not only in emission but also in absorption. The lower state has thus been assumed to be the ground state. It has now been established that t,his state, here designated the X state, is a ‘A state. This is based upon some det’ected R and P lines at the lowest J numbers. From the spectrogram of the O-O band at 6960.4 A of the D-,X system (see Fig. 2) it can be seen that the first R line is R (2%). This confirms the assumpt.ion made earlier (1) that the lowest state has s2 = 5/2. A decision between a ‘A s/t and a ‘@G,~state could not be made without the other set. of subbands. However, the corresponding 2A3/“-2A3j2 subbands of the E-X system were observed in the region 8200-8400 A where fortunately there are no overlapping bands. This made it possible to detect some interesting R and P lines with low J numbers in the 04 band. The turning R branch partly overlaps the R lines with low J numbers. However, just, beside and on the short wave1engt.h side of the R (7455) line, a weak line could be seen. This line is probably R (2%). It could be neither explained as an atomic line nor explained as a line of a band belonging to another molecule. A very weak line has also been seen at the place where the P (2%) line is expected to be situat’ed. No certain trace of the R (1%) line has been seen. According to theory, P (25; ) and R (1% ) should have the same intensity (9). The absence of the R (1%) line might be due to blending with a strong atomic line. As R (2%) and P (2%) should not be present in t,he alternative 2+~,2-2@~,Z transition, we have drawn t,he conclusion t,hat these bands are a 2A3/s-zA3/2 transition. A superscript a in Table III indicates that these lines have been discussed in this section or that they are overlapped. The Designation
of the States
The Ah:s for the systems are readily obtained from the band structure, the number of branches and their relative intensities. The two excited st’ates analyzed here were thus found to be a % and a ‘A. They have here been called D 2@ and E 2A. The earlier reported 211 and 24j states have then been assigned the capitals K and L, respectively. This means that the states earlier designat,ed I 2A, II ‘II, and III ‘@J(1) are now designated X 2A, K 2JI, and L %., respectively. The capitals have not been taken in alphabetic order as the ones omitted have been reserved for states which may be observed later on. The existence of additional stable states is very probable since two st.rong bands, one at 1.5 S46 cm-’
JANSSON
258
AND
SCULLMAN
and the other at 16 504 cm-‘, have been detected. These two bands have not yet, been analyzed. Their structure is different from that of the analyzed bands. Since no vibrational isotope splitting can be seen, the conclusion can be drawn that they are probably O-0 bands.
The normal state of the Ir atom is a % state and that of the C atom a 3P state. These states of the separated atoms give the following molecular states according to Wigner and Witmer (10): % (Ir)
+ “P(C)
---f [x+(3), I;-, II(3),
A(3), @((a), I’]2*4’6.
The normal “F state of the Ir atom is partly overlapped by the first excited state, another 4F state: which is also partly overlapped by the next excited st.ate and so on up t.o a rather high energy level. The number of possible low-lying molecular st,at,es is therefore quite numerous. However, t,he normal atomic states are sufficient to explain the observed molecular states. IrC is a heavy molecule with its two constituents from different periods of the periodic table. Moreover the Ir atom is a transition element whose outer 5cl and 6s electrons are of nearly the same energy. Assuming that the 1s electrons of the C atom are not influenced by the molecule formation (11), we suggest the following electron configuration for the ground state: ---u$‘~~n~$
--+ ‘A2 .
This is slightly different, from the one given earlier (1) which was based on a comparison with PbH. Electron configurations for the excited 2@, “A, and ‘II states are also easily obtained by exciting one of the outer electrons. These configurat,ions also predict a considerable number of “3 and 2JJ states. The above mentioned unanalyzed bands have a st’ruct,ure typical for bands with Ab = 0. They may be transitions between these predicted B or II stat,es. Dissocialim Energy A rough estimation
of t’he dissociation D.=&
Adding the excitation energies limits relative to the minimum tained:
energy
can be made using t’he formula
we e
of the electronic of the potential
states, the following dissociation curve of the X 2A6/s state are ob-
D, (X ‘AS/~) = 62000 cK1, D, (D 2+~,2) = 51000 cm-‘, D, (E 2A5,2) = 58000 cm-‘.
SPECTRUM
259
OF IrC
These energy values should be compared with that given by McIntyre et a.1. (12). Using mass spectrometric techniques, they obtained the dissociation value Do0 = (14S.4 f 3.0) kcal/mole for IrC. In cm-’ this would be almost 52 000, which is in rather good agreement with the above values. However, the dissociation products may be different. This is very probable since the possible states in the Ir atom overlap each other due to a strong multiplet splitting. TahleII. Warenumbere for the lines of the O-O,
l-l
and
2-2 bands of
* the II 2P7,2 - X 2A5,2 systems.
2.5
R195(J) 14354.26 355.11
:$J)
P193(5)
;::
2:; 2: 9.5 10.5 11.5
12.5 13.5 14.5 15.5 16.5 17.5 18.5 19;5
20.5 21.5 22.5
228.54 229.28
360.35 360.80 361.21
31.5 32.5 33.5 34.5 35.5 36.5 37.5 38.5 39.5 40.5 41.5 42.5 43.5 44.5 45.5 46.5
232.34 232.83
347.76
233.27 233.66 234.01
361.57 361.90 362.19 ::z1
343.05
324.44
340.36 339.38 338.36
318.75 316.75 314.73 312.66
362179 362.90 362.96 362.97
333.79
329.91
299.27
361.20 360.76 360.27 359.78 359.20 358.58 357.92 357.23 356.48 355.70
328.53 327.10
296.89 294.47 291.99 289.49 286.91 204.32 281.69 279.01 276.27
354.86
312.27 310.40 308.48 306.52 304.51 302.45
362.19 361.95 361.60
:55:*:5 352:09 351.06 350.01
234.31 234.57 234.78 235.94 235.06 235.13
310.54 308.37 306.16
27.5
30.5
229.98 230.65 231.28 23l.82
358.08 356.72 359.31 359.85
23.5 24.5 25.5 26.5
28.5 29.5
R(J) 14226.90 227.75
14350.56
325.64 324.13 322.56 320.96 319.30 317.62 315.88 314.10
273.48 270.66
258.92 255.8s
2-2 ____~.
l-l
I
J
Q(J)
P(J)
R(J)
Q(J)
14104.52 104.42 104.27 104.07 103.83
14081.25 080.17
103.57 103.22 102.85 102.43
075.36 074.04 072.68 071.27
101.93 101.41 100.86 100.28
069.81 06'3.33 066.78 065.18
099.59 098.86 098.11
063.54 061.87 060.14
097.32 096.52 095.64
058.35 056.51
094.71 093.74 092.62
052.71
14223.06 222.89 222.67 222.44 222.12 221.75 221.33 220.87 220.37 219.82 219.23 218.57 217&k 217.13 216.34 215.52 214.65 213.71
14202.46 200.71 198.91 197.05 195.17 193.24 $91.29 189.29 187.24 185.15 183.0? 180.80
235.16 235.16 235.11 235.00 234.82 234.62
212.74 211.73 210.68
234.38 234.07 233.74 233.39
205.99 204.71 203.36 202.02
178.57 176.30
232.96 232.50 231.98 231.41 230.80 230.13 229.43 228.68
200.60
169.20
199.13 197.63 I96.06
227.87 227.03
187.59 185.75
166.74 164.25 161.70 159.08 156.47 153.78 151.03 148.25
226.14 225.20
183.88 181.96
224.23 223.20 222.12 220.98
179.97 177.97 175.90 173.80
209.57 208.42 207.23
194.45 192.80 191.11 139.38
173.99 171.62
145.43 142.56 139.64 136.70 133.69 130.63 127.57
091.54 090.45 089.24
079.03 077.86 076.64
054.64
050.75 048.73 046.68 044.54 042.313
“60
JANSSON
Table
II(coatinued)
-.
o-o
-___ J
-_ _ 47.5 40.5
R193(J)
Q'93(J)
P193(J)
348.91 347.76 346.56 345.32
300.35 298.21 296.02
252.77 249.64 246.40
293.77
243.23
51.5 52.5 53.5 54.5 55.5 56.5 57.5 58.5 59.5 60.5
344.01 342.67 341.29 339.85 338.36 336.84
291.50 289.17 286.80 264.38 281.93
239.97 236.67
:::*'6:
274.25 271.62 268.90
61.5 62.5
328.53 326.69
63.5 64.5 65.5 66.5 67.5 60.5
324.84 322.93 320.96 318.96
49.5 50.5
69.5 70.5
AND SCULLMAN
331:9e 330.28
316.95 314.82 312.67 310.50 308.25
71.5 72.5 73.5 74.5
305.96 303.62 301.23
;z';
298.79 296.30
7715 78.5 79.5 80.5
293.76 291.17 288.53 285.84
El.5 82.5
283.12 280.32
83.5 84.5 85.5 86.5 87.5 88.5
277.41 274.59 271.62 268.64 265.62 262.53
89.5 90.5
259.38 256.18
91.5 92.5 93.5
252.92
279.41 276.86
266.15 263.37 260.53 257.64 254.71 251.74 248.71
233.29 229.07 226.44 222.93 219.40 215,83 212.20
Q(J)
219.81
171.64
218.59 217.31 216.01
169.44 167.20 164.90
214.65 213.23 211.77 210.28 208.72
162.55 160.16
207.13 205.48 203.79
P(J) 124.44 121.20
j R(J) I
165.04 160.82
229.57 226.20 222.81
156.54 152.21
040.18 037.97
117.95 114.65 111.31 108.04
157.73 155.24 152.71 150.13 147.50
147.84 143.44 138.96 134.50 129.92 125.30
201.38
120.65
197.63 193.84 190.00 186.11 182.17
115.95 111.20
Q(J)
086.74
197.23 193.36 1~9.46 185.51 181.51
236.15 232.89
---
088.02
204.80 201.03
239.37
219.38 215.85 212.31 208.72 205.08
R(J)
2-2
!
l-l
208.53
177.46 173.38 169.23
245.64 242.52
I j
106.39
178.17 174.15 170.08
*Mass l-be1 indicates that the branch shows isotope splitting.
SPECTRUM
TableIn.
Wsrenumbsra
for the
*A J __k”-o 1.5 2.5 3.5 4.5 2:: 7.5
R(J)
141.54a
150.73* 151.6P
140.39a 139.22 138.02 136.82
152.46'
11.5
156.31
12.5
157.03 157.71 158.39 159.00 159.61 160.19
17.5 18.5 19.5 ?0.5 21.5 22.5 23.5 24.5 25.5 26.5 27.5 28.5 29.5 30.5 31.5 32.5 33.5 34.5 :z*: 37:s 38.5 39.5 40.5 41.5 42.5 43.5 44.5 45.5 46.5 47.5 48.5 %ee
P(J)
149.82a
10.5
13.5 14.5 15.5 16.5
- *A
J/2
linea
of
261
I&
the O-O and l-l
of
*As/2
- *Q2 l-l
o-o
l-l
R(J)
banda
X :A suetem.
P(J)
R(J)
P(J)
R(J)
P(J)
12147.94a 14t~89~12142.64~
153.29a 154.09a 154.87 155.60
;:;
3/*
the
E *A-
OF
135.58 134.34 133.34
15110.93 111,61 112.28 112.92
131.71 130.36 128.99 127.63 126.20
113.52 114.10 114.66
124.76 123.29
160.73 161.23 161.72
121.81 120.27 118;7&
162.20 162.64 163.06 163.46 763.84 164.19 164.51 764.81 165.08
117.20 115.61
115.17 115.68 116.13 116.55 116.97
11j;9t3 112.34 110.66
117.34 117.70 118.02 118.31
108.97 107.23 1oj.4e
118.57 118.80 119.00
165.32
103.70 101.93
119.17 119.31
165.53 165.72
100.10 098.25 096.34 094.45 092.53 090.57
119.42 119.51 119.57 119.60 119.63 119.60
086.59 084.58 082.53
119.53 119.44 119.32 119.18
:z:: 166:17 166.26 166.32 166.36 166.39 166.36 166.31 166.23 166.11 765.96 165.78 165.55 165.33 165.09
Discussion
oee. 60
000.46
07+.04 071.85 069.64
12082.09 081.85 081.59
11990.97 988.73 986.48
118.98 118.75 118.50 778.22 117.92 117.58
067.39 065.12
081.32 081.03
984.17 981.85
117.22 116.82
078.33 07C.22
15088.44
087.09 065.72 084.33 082.88 081.42 079.94 078.44 076.90 075.31 073.71 072.07 070.41 068.73 067.01 065.28 063.51 061.70 059.s7 058.02 056.13 054.22 052.28 050.29 048.30 046.28
14951.59
044.24 042.13 040.03 037.88
15020.38 020.32 020.23 020.11 019.96 019.78 019.58
035.71
019.34
936.53
033.50 031.24 029.00 026.69
019.07 Olf3.78 018.45 018.08 017.68
934.29 931.99 929.65 927.28 924.88
017.24 016.77 016.29
922.45 919.97 917.47
024.39 022.03 ._ 019.66 017.25
_
949.53 947.45 945.34 943.18 941.02 938.80
.JANBSON AND SCULLMAN
’
J /
R(J)
p(J~! ____j_
P(J:
[ R(J)
P(J)
1 R(J)
P(J)
49.5 50.5
164.82 164.52
062.83 060.52
080.71 080.33
979.52 977.17
116.39
014.82
115.93
012.33
015.74 015.18
914.95 912.41
51.5 52.5 53.5 54.5 55.5 56.6
164.19 163.83 163.44 163.03 162.59 162.11 161.62 161.06 160.51
058.18 055.82
079.93 079.52 079.07 078.60
974.80 972.38 969.93 967.44 964.99 962.46
115.43 114.90 114.35 113.78
009.83 007.30 004.75 002.14
014.52 013.89 013.22 012.50
909.79 907.15 904.50 901.83
113.11 112.49
14999.52
011.75 010.99 010.17
899.07 896.31
57.5 58.5 59.5 60.5 61.5 62.5 63.5 64.5 65.5 66.5 67.5 68.5 69.5 70.5 71.5 72.5 73.5 74.5 75.5 76.5 77.5 78.5 79.5 80.5 81.5 82.5 83.5 84.5 85.5 86.5 57.5 88.5 89.5 90.5 91.5 92.5 93.5 94.5 ;65*: 97:5 98.5
053.42 051.00 048.56 046.07
159.96
043.59 041.06 03E.52 035.92
159.32 158.69 158.08
033.33 030.69 028.04
157.38 156.62
025.34 022.65
155.86 155.07 154.29 153.40 152.54
019.90 017.12
078.07 077.57 076.99 076.39 075.78 075.17
959.89 957.31 954.71 952.06
074.49 073.79
::69*::
073.04 072.28
943:9J3 941.21
014.32 011.50 00~.65
071.45 070.61 069.74 068.86 067.92 066.98
938.51 935.68 932.84 929.97
151.63 150.69
005.77 oon.e9
066.02 065.01
921.20 918.23
149.73 148.75 147.76 146.70 145.61 144.52 143.36 142.21
11999.93 996.97 993.97 990.95 987.89 984.87
063.95 062.87
915.23 912.21
141.02
975.44 972.26 969.05
139.78 lT8.50 137.22 135.90
981.75 978.61
965.79 962.54
134.55 133.14 131.70 130.26
;:;*z 952:54 949.11
.
;~,'%
.,
111.79 111.06 110.31 109.51 108.70 107.84 106.96 106.05 105.09 104.10 103.07 102.01 100.93 099.80 098.64 E$E o94:96 093.63 092.29 090.92 089.50 088.08 086.60 085.05 083.49 oa1.e7 080.21 078.53 076.81 075.05 073.26
128.80
945.73
071.43 069.50
127.26 125.76
942.34 938.81
067.57 065.58
124.19 122.56 120.91
935.30 931.80 92'3.23
063.57 061.50
119.26 117.53 115,eo
924.64 920.99 917.33
359.39 057.22
996.87 994.19 991.48 988.74 985.96
009.31 008.40 007.47
983.15 980.30
006.49 005.50
977.42 974.51 971.58 968.63
004.47 003.39 002.25 001.09
965.63 962.56
14999.87 998.66
959.50 956.42 953.30 950.13 946.93 943.70 940.44 937.15 933.82 930.44 927.06 923.62 920.14 916.62 913.10 909.53 905.90 902.27 898.56 894.83 891.08 887.26 883.39 879.50 875.59 871.63 867.61 063.60
893.53 890.70 887.82 884.91 881.98 879.00 876.00 872.94 869.85 866.76 863.60
SPECTRUM
Table of
the
system
D 2E7,2
-
and
l-l
D 2*7/2
the
-
j J
IV.
(J)\
Wavenumbers
X 2A5,2 band
X 2A5/2
E 2A5/2
of
the
I-O
2-2
band
of
the
E
X 2A
, 2 systemft
K 2Tr3j2
-
x
263
thelines
the
the
l-2
Q193(J)
for
system, of
OF IrC
2A5/2
-
K
2q2
P(J)
R(J)
2.5 3.5 4.5 2:: !': 9:5 10.5 11.5 12.5
14914.29 914.82 915.33 915.82 916.27 916.68 917.06 917.40
13.5 14.5 15.5 16.5 17.5 Is.5 19.5 20.5
71.5 22.5 23.5 24.5 25.5 26.5 27.5
13170.29 169.31 160.31 167.27 166.20 165.10
28.5
917.70 917.98 918.23 918.43 918.60
l4006.12 084.66 003.14 081.63
060.07 870.46 876.06 875.14 073.48 871.73 07O.Ol 868.25 066.30
19028.52 028.41 028.25 028.04 027.77 027.46 027.09 026.67 026.21 025.68
29.5 30.5
:%:I.
31.5 32.5 33.5 34.5 ;;.; 15241.84 239.99 238.10 3715 236.15 3e.5 234.15 39.5 232.08 40.5
161.60 160.33 159.04 157.70 156.30 154.87 153.40 151.90 150.39 148.85
025.12 024.47 023.80 023.04 022.26 021.42 020.54 019.56 018.60 017.56
147.24 145.56
016.45 015.28
41.5 42.5
229.92 227.73
l-2
bands
2A 5/z - x
-
x
2A5/2
2-$/2
l-l
2-2
R(J)
and
Q(J)
P(J)
19018.02 017.84 017.61 017.35 017.02 017.65 016.21 015.77 015.26
19015.46 014.30 013.03 011.77 010.47 009.12 007.68 006.21 004.72
014.71 014.05 013.36 012.66 011.90 011.09 010.22 009.32 008.39 007.35
003.24 001.64
006.27 005.17 004.01 002.76 001.51 000.22 18998. a4
997.40 995.94 994.43 992.85 991.26 989.59 987.85 986.07 984.24 982.36 980.45 978.44 976.42
'?z6e 996:49 994.70 992.85 990.94 988.97 906.94 984.90 ;x:: $4; 973:e9 971.55 969.16 966.72 964.22 961.64 959.07 956.41 953.68 950.92 948.09 945.23 942.31 ;:c:: . 933.25 930.08
264
JANSSON
Table IV D 2+2
AND
SCULLMAN
(continued). - K 2A5,2
E 2A5,2 - K 2A5,2
K 2r
2-2
R(J)
J 43.5 44.5 45.5
225.50 223.20 220.85
46.5 47.5 40.5 49.5 50.5
218.43
51.5 52.5 53.5
205.65 202.94 200.17
54.5 55.5 56.5
197.35 194.48 191.56 188.59
,,-_
57.5 58.5 59.5
66.5
-i-T P-(J)
143.86 142.12 140.37
215.97 213.46 210.90 noe.jo
Q(J)
P(J)
014.05 012.77 011.43 010.08 008.60 007.11
969.99 967.74 965.43 963.06 960.65 958.18
926.91
005.57 003.96
955.67 953.02
906.79 903.08
002.28 000.54 lB998.78
950.44 947.74 944.97 942.23
899.48 695.98 892.32 ma.55 884.64 13130.68 076.76 872.70 868.76 864.68
185.57 182.49 179.33
984.72
61.5 62.5
982.49 980.19
63.5 64.5 65.5
977.83 975.39 972.91
indicates
that
Table V. kvenumbers
the
branch
2A
5/2 _ .----
R(J)
996.95 995.03 993.12 991.09 989.04 986.90
*Mass label
- x 3/2
shows
isotope
;:c:: 933:44 930.45 927.31 924.17 920.96 917.69 914.38 911.02
923.69 920.41 917.09 913.70 910.29
860.53 856.32 852.06 847.74
907.59
splitting.
for the lines of the O-O and 1-O bands
system and of the O-O band of the L 26
20819.54 820.16
::: 4.5
19236.44 236.28 236.08
2:;
235.53 235.83
19228.96
7.5 ;::
235.19 234.38 234.80
227.63 224.81 226.23
10.5
233.92
223.35
820.71 821.17 821.56 821.87 822.08 822.20 822.25
20815.46 014.97 814.38 813.73 '312.95 812.12 811.21
SPECTRUM
Table
OF IrC
V (oontinued).
.~-
K 27/*- x %,* o-o J
R(J)
11.5 12.5 13.5 14.5 15.5 16.5 17.5 18.5 19.5 20.5 21.5 22.5 23.5
1-o _ _~~_
Q(J)
P(J)
233.38
221.85 220.29 218.68 217.03 215.34 213.58 211.78 209.92 208.06 206.10
232.80 232.20 231.56 230.87 230.12 229.33 228.51 227.63 226.71
204.11 202.11 200.07 197.97 195.82 193.60 191.35
L 2M;/2 - x 2A5/2 ______o-o ___~~ ~-.~ --
Q”‘(J)
R lg3(J)
Q”‘(J) 810.23 809.11 007.92 806.65 005.20 803.81 802.29 800.66 798.95 797.14
20799.12 797.05
20059.61 058.56
822.20 822.07 821.85 821.55 821.14 820.64 820.07 819.40 8113.61 817.79 816.83 815.82 014.68 813.49 812.18 810.82 809.36 007.7% 806.14 804.40
795.25 793.25 791.18 :,"z*;," 784:44 782.01 779.52 776.90 774.19
774.59 771.63 768.61 765.51 762.30 759.02
802.57 800.66 798.63 796.53
771.41 768.54 765.58 762.51
;;:*i: 789:6g 787.21 704.67 782.01
::z 752:79 749.36
25.5 26.5 2’7.5 28.5 29.5 30.5
247.95 247.74 247.49 247.20 246.07 246.46
225.75 224.75 223.67 222.55 221.39 220.19 218.92 217.64 216.27 214.91
31.5 32.5 33.5 34.5 35.5 36.5 37.5 38.5 39.5 40.5
246.02 245.56 245.02 244.43 243.82 243.14 242.39 241.60 240.77 239.89
213.40 211.99 210.46 208.88 207.25 205.59 203.84 202.08 200.27 198.40
181.88 179.40 176.88 174.32 171.72 169.02 166.30 163.52 160.71 157.86
41.5 42.5 43.5 44.5 :2*: 47:5 48.5 49.5 50.5
238.99 238.02 236.97 235.88 234.76 233.59 232.34 231.04 229.70 228.32
196.46 194.47 192.48 190.41 188.29 186.12 183.89 ls1.64 179.31 176.93
154.95 152.01 148.98 145.94 142.83 139.67 136.46 133.21 129.90 126.54
020.34 017.88 015.40 012.87 010.29 007.64 004.94 002.17 19999.38 996.50
51.5 52.5 53.5 54.5 55.5
226.89 225.41 223.84 222.27 220.62
174.51 172.05 169.50 166.94 164.30
123.13 119.67 116.14 112.62 109.00
;;;*:t 907147 984.32 981.11
24.5
.-_
19240.12
265
189.04,
106.77 184.33
Z,'E 054:98 053.67 052.26 050.80 049.29 047.68
:;z*:; . 773.52 770.50 :z:*:i 760:88 757.51 754.01 750.45 746.78 743.03
Plg3(
J)
;;:*;z 790:40 787.99 785.49 782.91 780.23 777.45
::zi 748:57 744.92
:::'z .
741.19 737.34 733.40 729.39 725.30 721.10 716.82 712.49 700.03 703.47
738.57 734.79 730.91 726.95 722.90 718.75 714.53 710.21 705.79 701.27
698.83 694.11 689.29 684.36 679.37 674.27 669.09 663.82 658.46 653.00
696.66 691.95 687.16 682.27 677.30
647.44 641.80 636.13 630.30 624.38
JANSSON
266 Table
AND
SCULLMXN
V (continued).
VT
2 K
3/z
- *
2 d5/2
---.0-o
L “7,2 .___
1-O
- ’
‘* 5/2
o-o Qlg3(J)
P’93(
J)
Q(J)
P(J)
Q’93(J)
Rrq3(J)
;:4”;:
727.04 722.82 718.50 714.09 709.60
672.22 667.06 661.79 656.45 651.00
:;;*:z .
704.98 700.27 695.46 690.57 685.59 680.49 675.31 669.99 664.60 659.14
645.46 639.89 634.13 628.31 622.39 616.30 610.27 604.07 597.76 591.37
586.92 580.35 573.70 567.00 560.i6 553.21 546.13 539.04 531.80 524.48
653.58 647.00 642.13 636.33 630.35 624.27 618.09 611.83 605.43 598.98
584.87 578.31 571.62 564.83 557.92 550.94 543.88 536.71 529.42 522.01
517.07 509.53 501.94 ",z:: 478154 470.51 462.44 454.26 445.98
81.5 82.5 83.5 84.5 85.5 86.5 87.5 88.5 89.5 90.5
592.45 585.75 578.97
514.57 506.98 499.32 491.52 483.64 475.65 467.58 459.41 451.13 442.75
437.59 429.10 420.53 411.84 403.11 394.17 385.21 376.13 366.94 357.66
91.5 92.5 93.5 94.5
521.13 513.44 505.64 497.72 489.70 481.55 473.30
56.5 57.5 58.5 59.5
218.93 217.16 215.33 213.44 211.50
161.61 150.86 156.08 153.22 150.32
105.33 101.61 097.66 094.03 090.15
61.5 62.5 63.5 64.5 65.5 66.5 67.5 68.5 69.5 70.5
209.49 207.42 205.37 203.18 200.95 190.67
147.37 44.35 41.28 38.16 34.97 31.74 28.43 25.07 21.68 18.20
086.22 082.24 078.20 074.11 069.95 065.76 061.49 057.20 052.83 048.40
71.5 72.5 73.5 74.5
86.47 83.85
;z’: . 77.5 78.5 79.5 80.5
;x; 69170 166.79
114.68 111.09 107.47 103.75 099.98 096.16 092.27 ose.32
043.88 039.34 034.74 030.09 025.36 020.58 015.74
60.5
;z’: 97:5 98.5 s9.5 100.5 101.5 102.5 103.5 104.5
96.3+ 93.98 91.54 B9.04
81.18
78.42
971:12 967.63 964.10 960.52 956.86 953.14 949.34 ;:z;: .
:::*z 558:OZ 550.84 ::z*:: 526:70
--
618.37 612.27 606.08
:;z';: 448IOl
:;:*;;s 381:,2 371.92 362.60 353.16
348.27 338.76 329.18 319.50 309.71 299.79 289.81 297.72 269.52 259.19
439.35 430.58 421.70 412.70
343.60 333.98 324.23 314.34
248.77 238.25 227.62 216.90
:::'z: 416198 408.14
-.--
*
Mass
label
indicates
that
the
branch
shows
isotope
splitting.
SPECTRUM
OF IrC
267
ACRNOWLEDGMF,NT We thank Professor Albin Lagerqvist for his never failing willingness to discuss our work, for reading though this article and making a number of useful suggestions, and Dr. Lennart Klynning for advice concerning the computer calculations of the spin-orbit coupling constants. We also thank Mrs. Marianne Nordin for the drawings and Mr. Ants Paas for the spectrogram. RECEIVED:April 24, 1970 REFERENCES 1. K. JANSSON,R. SCULLMAN, ANDB. YTTERMO,Chem. Phys. Lett. 4, 188 (1969). R. H. NEUHAUS,R. SCULLMAN, ANDB. YTTERMO,2. Naturforsch. 2Oa, 162 (1965). 3. A. LAGERQVIST, H. NEUHAUS,ANDR. SCULLMAN, 2. Nat,urforsch. 20a, 751 (1965). 4. G. EDVINSSON,I. KOPP, B. LINDGREN,ANDN. ASLUND,Ark. Fys. 26,95 (1963). 6. R. S. MULLIKEN,Rev. Mod. Phys. 2, 60 (1930). 6. G. M. ALMY ANDR. B. HORSFALL,Phys. Rev. 61, 491 (1937). 7. L. KLYNNING,B. LINDGREN,AND N.&LUND, Ark. Fys. 30, 141 (1965). 8. N. ASLUND,Ark. Fys. 30, 377 (1965). 9. I. Kovbcs, “Rotational Structure in the Spectra of Diatomic Molecules,” p. 121. Adam Hilger, London, 1969. 10. E. WIGNERANDE. E. WITMER,2. Phys. 61,859 (1928). f 1. J. E. LENNARD-JONES, Trans. Faraday Sot. 26, 668 (1929). 12. N. S. MCINTYRE,A. V. AUWERA-MAHEIU,ANDJ. DROWART,Trans. Faraday Sot. 64, 3006 (1968).