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Revised molecular constants for the E 1Σ state of the diatomic CuI molecule
22Ocrobcr
CHCMICALPHYSICSLE-ITCRS
Volume 91, number 3
1982
REVISED MOLECULAR CONSTANTS FOR THE E t C STATE OF THE DIATOMIC Cul MOLECULE KP. l’gappan NAIR
Rcccrrcd 9 Auysr
A
1982
k&1-squares compurcr
program has been used IO fit rhr obwvcd
system of Ihe Cul molecule. hlolccul~r CONI~IS I~onal
and crntnfuEal consrams
oi rhc
rotu~onal hnc poswons of Ihc 11I r-S
E smc habc been
rcvlsed and hlghcr wbrxronal
*X band
wrms m the rcaa-
hzwc been obrancd
The copper Iodide molzcule has been subject fo many spzctroscopic investigations. The electronic spectrum of Cd was fust investigated by hlulliken [I] and Rnschl [2] m the visible region. Some years ago we studled the high-resolution spectra of the E-X and C-X band systems of 63Cu1271 [3,4] _The only laser spzctroscopic study was on the A-X band system, as this is the only system which lies m the commonly used rhodamine 6G frequency region [S, 61. The molecular constants deduced from our earher studies [3] were obtained by the usual graplucal methods with the aid of combmarion differences as
describedby Herzberg[7]. Thu methodhas INS weaknessof Ien accuracy, even thou& ir helps m tie asof the rotatlonal quantum numbers. A simultaneous fit of the two electronic states is always hampered by the correlation among mokcular parameters of the two electronic states mvolved. However, if accurate molecular constanfs are available for one of the states from other methods, tk drawback can be fully avolded bytittingthe parameters of rhe othzr electronic state. The microwave rotational spectra of Cut have recently be2n studied by Manson et al. [8] and also by us [9] and the ground-state molecular constants are very accurately known. Hznce it was thought worthwhile to reanalyse the rotational lines of the E-X system by a recently written least-squares fit computer program [IO] which fit the line frequencies directly. The program, which is m Fortran was origmally written to tit the line frzquencies of a 2C-71: molz-
cule.Theinputsare initialvaluesof B~,(Y~,ye, De, & for the upper and lower states and the spm-rotation parameters 7C-R, a_, for the two states and the observed frequencies with then rotatIonal and vlbratlond quantum numbers. However, for a 1Z-1 Z type transition, as in the present case, the spin-rotation parameters an meanmgless and can be kept zero in the program. The frequencies are then calculated by the following formulaR(J) = uo + F’(J t 1) - F”(J) , PQ=v,+F’(J-
I) -F”(J),
whew
signment
IQ = Ye + w;(IJ’+ -
cJJ(u” +
f)
f)
-
w&u’
t o,x~(u”+
i=(J) = B,J(J+ I) -D&J+
+ $)’ ;>z
,
I)? ,
B,=B,-cr,(ut~)ty,(u+~)‘, Dv = D,+&(u+;)
.
Thejacobian matrix is built analytically in the main program and a hbrary least-squares subroutine is used for the least-squares fit. The earher measurements [3] of the rotational
transitions of the (4,0), (3,O). (2,0), (1 ,O), (l,I), (0,l) and (02) bands of the E-X system of CuI have been fitted. The ground-state molecular constants have been kept constant at the microwave w&es. The fit
0 009-2614/82/0000-0000/S 02.750 1982North-Holland
771
Volume 91. number 3
CHELIICALPHYSICS LETTERS
Table 1 Xlolrcular constants ior the k *S SIX~oi the %u cule a)
“‘1 molc-
24001 698 (14) cm-’ 229 SO8( 14) cm-’ 0.9856 (28) cm-t
Table 3 Rotaoonal constants OFthe C t I: state oi the 63Ctttz71 moleculea) 0.068233 (18) cm-t 2 42(16)x 1O-8 cm-t X851.29(4) cm-t 21587 51(-I) cm-t
Bu=o Du=o “0 0 “OJ
0 0656019 (40) cm-t 0 0002806 (34) cm-’ -1.36 (46) x 10” cm-’ 2.158(3-t) X 10m6 cm-’ 3 96 (7-t) x IO-to cm-t
22 October 1982
a) The ground-ate corwmts ~erc kept constant dunng the tit [B]. For the lmc frcqucnclcs set rci. [3] Errorsquotcd are tao standard devlarlons oi the fit.
1,17lSO(12)A a) The ground-state rotatton.tl constants uere kept constant durmc the tit [B]. For the iuw frquenctcs see rei. [3]_ Errors quoted are two standard dewtttons of the fit
Tsblc Z Cortclstton co?ilictcnts among rartous constants oirhc I: state oiCul 7-c
WeXc
Be
oe
I .ooo 0 3-M 0 720 0 823 0 04’ -0 050
1000 0 777 0.431 0 890 -0.866
1.000 0 872 0 479 -0530
DC
pe
1.000 -0 953
1.000
I 000
-0 833 -0 677 -0 801 -0.77 I -0 55-l -O.SSS 0 532
I 000 0 956 0316 0.801 0 771 0 209 -0.2-16
more accurate values of the molecular constants for the excitrd E state and by this method htgher
gives
vtbrattonf terms in the rotsttonti and centrtfugal constants could be determmed. Altogether 1760 lures
were uzd m the fit and a global fir ofall lutes gives the molecular constants oi the E state as in table 1. The standard devration of the tit, as dzfiied by u = [z(obs
- al)‘&\-
comparable
-
I)] tc,
is 0.042
cm-’
with the average measurement
whtch is accuracy
oi0.05 cm-*. The correlation among the various parameters is shown m table 2. The rotational lures of the (0.1) and (0.0) bands of the C 1Z-X 1B band have also been fitted by the same program by fittmg the lrnes of the two bands separately and the results are shown m table 3.
1000 0 080 -0 084
References (11 R S. hlulhken. Phys. Rev. 26 (1925) 1. [‘] R Rtrschl, Z Phystk12(1927) 172. [ 31 K P R. Nan and K N. Upadhya, Can. J. Phys 44 (1966) 1167 [-I] K P.R. Nate and D_R..Rat.Can. J.Phys 45 (1967) 2610. [S] C.Y.R. Wu and D A. Dows. J. hfol Spectry
58 (1975)
38-t [6] S B. RX and DJi. Rcu. Chem. Phys. Lrtters 80 (1981) 606.
[ 7] C. Heaberg, Spectra of dutomic molcculcs (Van Nostrand. Ptmceton, 1950). [S] C L. Mattson. F C. Delucn and W.Cordy. J. Chem. Phys 62 (1975) 4796. [9] K.P.R. Nair, J. Hoeft and E. Ttemann, Z. Natutiotsch 32a (1977) 1053. [lo] R P R Nate. A Least-Squares FitComputer Program ior Z-X Trartsttions, unpublished.
CHCMICALPHYSICSLE-ITCRS
Volume 91, number 3
1982
REVISED MOLECULAR CONSTANTS FOR THE E t C STATE OF THE DIATOMIC Cul MOLECULE KP. l’gappan NAIR
Rcccrrcd 9 Auysr
A
1982
k&1-squares compurcr
program has been used IO fit rhr obwvcd
system of Ihe Cul molecule. hlolccul~r CONI~IS I~onal
and crntnfuEal consrams
oi rhc
rotu~onal hnc poswons of Ihc 11I r-S
E smc habc been
rcvlsed and hlghcr wbrxronal
*X band
wrms m the rcaa-
hzwc been obrancd
The copper Iodide molzcule has been subject fo many spzctroscopic investigations. The electronic spectrum of Cd was fust investigated by hlulliken [I] and Rnschl [2] m the visible region. Some years ago we studled the high-resolution spectra of the E-X and C-X band systems of 63Cu1271 [3,4] _The only laser spzctroscopic study was on the A-X band system, as this is the only system which lies m the commonly used rhodamine 6G frequency region [S, 61. The molecular constants deduced from our earher studies [3] were obtained by the usual graplucal methods with the aid of combmarion differences as
describedby Herzberg[7]. Thu methodhas INS weaknessof Ien accuracy, even thou& ir helps m tie asof the rotatlonal quantum numbers. A simultaneous fit of the two electronic states is always hampered by the correlation among mokcular parameters of the two electronic states mvolved. However, if accurate molecular constanfs are available for one of the states from other methods, tk drawback can be fully avolded bytittingthe parameters of rhe othzr electronic state. The microwave rotational spectra of Cut have recently be2n studied by Manson et al. [8] and also by us [9] and the ground-state molecular constants are very accurately known. Hznce it was thought worthwhile to reanalyse the rotational lines of the E-X system by a recently written least-squares fit computer program [IO] which fit the line frequencies directly. The program, which is m Fortran was origmally written to tit the line frzquencies of a 2C-71: molz-
cule.Theinputsare initialvaluesof B~,(Y~,ye, De, & for the upper and lower states and the spm-rotation parameters 7C-R, a_, for the two states and the observed frequencies with then rotatIonal and vlbratlond quantum numbers. However, for a 1Z-1 Z type transition, as in the present case, the spin-rotation parameters an meanmgless and can be kept zero in the program. The frequencies are then calculated by the following formulaR(J) = uo + F’(J t 1) - F”(J) , PQ=v,+F’(J-
I) -F”(J),
whew
signment
IQ = Ye + w;(IJ’+ -
cJJ(u” +
f)
f)
-
w&u’
t o,x~(u”+
i=(J) = B,J(J+ I) -D&J+
+ $)’ ;>z
,
I)? ,
B,=B,-cr,(ut~)ty,(u+~)‘, Dv = D,+&(u+;)
.
Thejacobian matrix is built analytically in the main program and a hbrary least-squares subroutine is used for the least-squares fit. The earher measurements [3] of the rotational
transitions of the (4,0), (3,O). (2,0), (1 ,O), (l,I), (0,l) and (02) bands of the E-X system of CuI have been fitted. The ground-state molecular constants have been kept constant at the microwave w&es. The fit
0 009-2614/82/0000-0000/S 02.750 1982North-Holland
771
Volume 91. number 3
CHELIICALPHYSICS LETTERS
Table 1 Xlolrcular constants ior the k *S SIX~oi the %u cule a)
“‘1 molc-
24001 698 (14) cm-’ 229 SO8( 14) cm-’ 0.9856 (28) cm-t
Table 3 Rotaoonal constants OFthe C t I: state oi the 63Ctttz71 moleculea) 0.068233 (18) cm-t 2 42(16)x 1O-8 cm-t X851.29(4) cm-t 21587 51(-I) cm-t
Bu=o Du=o “0 0 “OJ
0 0656019 (40) cm-t 0 0002806 (34) cm-’ -1.36 (46) x 10” cm-’ 2.158(3-t) X 10m6 cm-’ 3 96 (7-t) x IO-to cm-t
22 October 1982
a) The ground-ate corwmts ~erc kept constant dunng the tit [B]. For the lmc frcqucnclcs set rci. [3] Errorsquotcd are tao standard devlarlons oi the fit.
1,17lSO(12)A a) The ground-state rotatton.tl constants uere kept constant durmc the tit [B]. For the iuw frquenctcs see rei. [3]_ Errors quoted are two standard dewtttons of the fit
Tsblc Z Cortclstton co?ilictcnts among rartous constants oirhc I: state oiCul 7-c
WeXc
Be
oe
I .ooo 0 3-M 0 720 0 823 0 04’ -0 050
1000 0 777 0.431 0 890 -0.866
1.000 0 872 0 479 -0530
DC
pe
1.000 -0 953
1.000
I 000
-0 833 -0 677 -0 801 -0.77 I -0 55-l -O.SSS 0 532
I 000 0 956 0316 0.801 0 771 0 209 -0.2-16
more accurate values of the molecular constants for the excitrd E state and by this method htgher
gives
vtbrattonf terms in the rotsttonti and centrtfugal constants could be determmed. Altogether 1760 lures
were uzd m the fit and a global fir ofall lutes gives the molecular constants oi the E state as in table 1. The standard devration of the tit, as dzfiied by u = [z(obs
- al)‘&\-
comparable
-
I)] tc,
is 0.042
cm-’
with the average measurement
whtch is accuracy
oi0.05 cm-*. The correlation among the various parameters is shown m table 2. The rotational lures of the (0.1) and (0.0) bands of the C 1Z-X 1B band have also been fitted by the same program by fittmg the lrnes of the two bands separately and the results are shown m table 3.
1000 0 080 -0 084
References (11 R S. hlulhken. Phys. Rev. 26 (1925) 1. [‘] R Rtrschl, Z Phystk12(1927) 172. [ 31 K P R. Nan and K N. Upadhya, Can. J. Phys 44 (1966) 1167 [-I] K P.R. Nate and D_R..Rat.Can. J.Phys 45 (1967) 2610. [S] C.Y.R. Wu and D A. Dows. J. hfol Spectry
58 (1975)
38-t [6] S B. RX and DJi. Rcu. Chem. Phys. Lrtters 80 (1981) 606.
[ 7] C. Heaberg, Spectra of dutomic molcculcs (Van Nostrand. Ptmceton, 1950). [S] C L. Mattson. F C. Delucn and W.Cordy. J. Chem. Phys 62 (1975) 4796. [9] K.P.R. Nair, J. Hoeft and E. Ttemann, Z. Natutiotsch 32a (1977) 1053. [lo] R P R Nate. A Least-Squares FitComputer Program ior Z-X Trartsttions, unpublished.