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Transition probabilities derived from emission measurements for the system 5p3-5p26s of neutral antimony
1. @ant. Spctmsc. Rodtat.TransferVol. 24, pp. 133436 @J Pergamon Press Ltd.. 1980. Printed in Great Britain
TRANSITION PROBABILITIES DERIVED FROM EMISSION MEASUREMENTS FOR THE SYSTEM 5p3-5p26s OF NEUTRAL ANTIMONY Y. GUERNand J. LOTRIAN FacultC des Sciences et Techniques, 29283Brest Ctdex, France (Received 5 December 1979) Abstract-Decay branching ratios have been measured for the transitions from seven levels of SbI (configuration 5~~6s) observed in a hollow cathode discharge in the 180-400 nm spectral range. Using the lifetimes found in the literature, a set of absolute transitions probabilities is given for 31 lines. INTRODUCTION
There are very few results concerning the probabilities of the transitions of neutral antimony in the U.V. Beside the values given by Corliss and Bozman,’ we found only an experimental determination for the 231.2 nm line by Lvov* and the theoretical work of Holmgren.3 The present work gives decay branching ratios for transitions from the even upper levels 4P1,2,4P3,2, 4Ps,2,2P,j2,2P312, 2D3,2,and 2Df,2in the configurations 5p26s to the odd levels 4S’$2,‘@12,2D$2,2Py,2, and 2P$2 of the configuration 5p3. From the lifetime values given in the literature, transition probabilities are derived and compared with the other values. EXPERIMENTAL
METHOD
In the present work, we used the experimental method that we described in several previously published papers on GeI, PbI, BiI, and AsI.~ To extract individual transition probabilities Aik from the lifetimes 7i = l/CiAii, the decay branching ratios Rik = Aik/CjAij are determined from intensity measurements of the spectrum emitted by a hollow cathode. The lamp is filled either with neon or argon as carrier gas to avoid interferences between the lines of SbI and the carriers. To prevent self-reversal, we used low excitation currents (from 6 to 10 mA). The spectrum is recorded on a 1 m Romand-Vodar monochromator and a 3.4 m Ebert-Fastie spectrometer. To measure the ratio of intensities between neighbouring lines at 259.8 nm (4P51r2D$2,2P,,2-2D$2, and a separation of about 5 pm), we had to use a Fabry-Perot interferometer. The accuracy of the calibration (deuterium lamp and tungsten ribbon lamp) and the stability of the hollow cathode lamps lead us to estimate the error to be about 8% for the branching ratios. However, the error may be larger for the weakest branches (up to 25%). RESULTS
AND DISCUSSION
In Table 1, the branching ratios are given below the wavelengths (in nm) of the transitions. The symbol “-” in the table means that the line was not observed in the spectrum. For antimony, lifetimes have been measured using the Hanle method of Belin et al.,5 the beam-foil technique of Andersen et al.,6 and the delayed coincidence technique of Osherovich and Tezikove7 These values are given in Table 2 and are expressed in ns. In the transitionprobability determinations we used the weighted means given on the lowest line, with allowance for errors estimated given by different authors. Our results (transition probabilities and oscillator strengths) appear in Table 3 and are compared with the theoretical values of Holmgren? which were calculated by using the optimized Hartree-Fock-Slater method. The agreement is quite good but there are some discrepancies for the weakest lines. The experimental values in the present work are often between the two theoretical results obtained, respectively, with the dipole-velocity (DV) approximation and the dipole-length (DL) approximation. However, the agreement is generally better with the results of the dipole-length (DL) approximation. For the ‘Pl12 level, the values of Aik for the two strongest lines we obtained are much lower even than the value obtained from the DV approximation. We, therefore, expect a correspondingly lower value for the lifetime of the 2P1,2level. To check this 133
134
Y. GUERN
and J.
LOTRJAN
Table I. Values of branching ratios (lower line) and wavelengths (upper line) for transitions in nm. -lower
level: 5P3
4s” 3/Z
upper
4P
level: 5~~6s
l/2
43249 4
‘312
45945 4
‘5f2
48332
20 D3/2
’
0
8512
2D0 512
’ cm-l
9854
’ cm-’
2Po l/2 16385
’ cm-’
2P0 312 18464
’
231.2
287.8
372.3
403.4
cm-’
0.793
0.200
0.0041
0.003
’
217.6
267.1
277.0
338.4
363.8
cm-’
0.857
0.041
0.086
0.007
0.009
’
206.9
251.1
cm _*
0.890
259.8
334.6
0.103
0.006
’ cm
-I
2 p1/2 46991
’
212.8
259.8
326.8
cm -1
0.039
0.778
0.183
350.5
2 ‘3/Z 49391 2
D3/2
’
202.4
244.6
252.9
303.3
323.3
cm _,
0.028
0.026
0.726
0.094
0.126
’
181.0
214.0
220.3
257.4
271.9
cm-’
0.151
0.644
0.007
0.068
0.131
2D5,2
’
179.4
5572%
cm-’
55233
211.7
217.9
268.3
0.015
0.908
0.076
hypothesis, we determined a new lifetime value for this level by comparing the lifetimes of two levels on the assumption that the population of SbI levels are in statistical equilibrium. For the two levels identified by the subscripts 1 and 2,
T,,T2
=
81 exp g2
exp
(-NkTGi4ih2i (-EZ/WZjZ*jAlj’
A
E, 45
50
55
l
10bll-’
Fig. I. Determination of the excitation temperature from a plot of In (liiAijlgiAii)vs Ei.
135
Emission measurements for the system 5p3-Sp*6s of neutral antimony Table 2. Values of lifetimes in ns. Levels
4P
(5p26s)
ANDERSEN
4
4 112
5.0 +
p3/2 0.4
2 '512
2 PI/2
4.9 +
0.5
4.8 + 0.4
5.1 +
0.6
4.8 + 0.4
4.6 +
0.5
5.5 + 0.7
2 '3/Z
2 n5/2
%2
4.0
+ 0.3
4.3
+ 0.4
3.7 +
0.4
3.8 +
0.3
6
et al. BELIN
5
et al. OSRBROVICH TEZIKOV'I and
I
4.3 -+ 0.4
used
I
4.1
I
4.9
I
4.9
5.2 + 0.5
1
5.2
1
4.1
1
3.7
)
3.8
The excitation temperature (about 8200 K) was determined by plotting In (liiAij/giAij)vs Ej (Fig. 1) for all of the levels except the 2PI,2level. We obtained a straight line with a correlation coefficient of 0.91. The estimated lifetime of the 2P1,2level is 3.7 + 0.7 ns. The point obtained from the value 5.2 ns for the 2Pl,2 lifetime by Osherovich and Tezikov’ is much higher than our value. We expect a lifetime 7 near 3.7 ns. The new values of Aik and f are identified in Table 3 with asterisks. Table 3. Values of transition nrobabilities and oscillator strentihs. The numbers in oarentheses represent powers . of 10: DV =Adipole-velocityapproximation; DL = dipole-length approximation. Aik
Level
(s-‘1,
Aik
z.
l/2 ' 4.7
4p3/2 z-
'
4.9
4 '512 z-
'
4.9
2 pl/2 z-
5.2
r+-
3.7
'
'3/Z z-
z-
983(5)
201(6)
0.068
287.8
424(5)
315(5)
423(5)
0.027
372.3
863(3)
261(4)
llZ(4)
0.002
403.4
637(3)
633(3)
478(3)
0.001
217.6
175(6)
957(5)
193(6)
0.124
267.1
837(4)
334(4)
839(4)
0.009
277.0
176(6)
124(5)
182(5)
0.013
338.4
l42(4)
791(3)
734(3)
0.005
363.8
175(4)
241(4)
139(4)
0.003
206.9
181(6)
952(5)
188(6)
0.174
373(3)
239(3)
259.8
ZlO(5)
167(5)
329(5)
0.021
334.6
128(3)
lOZ(3)
117(l)
0.003
746(4)
105(5
291(4)
142(5)
0.003
0.004*
259.8
150(6)
Zll(6
218(6)
311(6)
0.076
0.107
325(5)
495(5
0.056
0.079
492(5)
479(5)
__
158(4)
734(3)
'
202.4
683(4)
323(3)
433(4)
244.6
630(4)
138(5)
Zll(5)
0.006
252.9
177(6)
183(6)
279(6)
0.113
303.0
230(5)
364(5)
422(5)
0.063
323.3
307(5)
400(5)
379(5)
0.048
'
3.7
7
z-
3.8
'
0.004
181.0
408(5)
ll8(4)
527(4)
0.020
214.0
174(6)
760(5)
152(6)
0.119
220.3
l79(4)
613(4)
400(4)
0.001
257.4
181(5)
ll9(5)
l90(5)
0.036
271.9
354(5)
105(6)
152(6)
0 039
179.4 2D5/2
LVOVi
0.041
212.8
350.5
4.1
2D3/2
169(6)
251.1
work
J_
231.2
326.8
2
DL
f,
f, present
Dv 4P
(s-‘1,
work
present
510(4)
139(5)
211.7
402(4)
303(5)
463(5)
0.004
217.9
239(6)
ll7(6)
223(6)
0.170
268.3
201(5)
240(5)
339(5)
-
0.032
136
Y. GUERN and J. LOTRIAN
The weaker value of 0.041 for the oscillator strength obtained by Lvov2 for the 231.2 nm line may be explained by the possible presence of Sbz molecules in the vapor of his graphite cell. We also note that the higher ratio f(217.6)/f(231.2) = 2.46 was obtained by Muradov and Muradova* instead of the value 1.82 obtained in the present work. REFERENCES 1. C. H. Corliss and W. E. Bozman, Monograph No. 52 N.B.S., Washington DC. (1%2). 2. B. V. Lvov, Op!. Spectrosc. (USSR) 10, 15 (1965). 3. L. Holmgren, Physica Scripta 11, 15 (1975). 4. J. Lotrian, Y. Guern, J. Cariou, and A. Johannin-Gilles, J. Phys. B 11, 2273 (1978); Y. Guern, J. Lotrian, A. Bideau-Mehu, and A. Johannin-Gilles, 1. Phys. B 11, 3821 (1978);J. Lotrian, Y. Guern, J. Cariou, and A. JohanninGilles, lQSRT 21, 143(1979);J. Lotrian, Y. Guern, and J. Cariou, J. Phys. B 13,685 (1980). 5. G. Belin, S. Garpman, L. Holmgren, and S. Rydbcrg, Physica Scripta 9,213 (1974). 6. T. Andersen, S. Worre-Jgrgensen, and G. Serensen, J. Opt. Sot. Am. 64,891 (1974). 7. A. L. Osherovich and V. V. Tezikov, Opt. Spectrosc. 43,612 (1977). 8. V. G. Muradov and 0. N. Muradova, Zh. Prikl. Spektr. 29,599 (1978).
TRANSITION PROBABILITIES DERIVED FROM EMISSION MEASUREMENTS FOR THE SYSTEM 5p3-5p26s OF NEUTRAL ANTIMONY Y. GUERNand J. LOTRIAN FacultC des Sciences et Techniques, 29283Brest Ctdex, France (Received 5 December 1979) Abstract-Decay branching ratios have been measured for the transitions from seven levels of SbI (configuration 5~~6s) observed in a hollow cathode discharge in the 180-400 nm spectral range. Using the lifetimes found in the literature, a set of absolute transitions probabilities is given for 31 lines. INTRODUCTION
There are very few results concerning the probabilities of the transitions of neutral antimony in the U.V. Beside the values given by Corliss and Bozman,’ we found only an experimental determination for the 231.2 nm line by Lvov* and the theoretical work of Holmgren.3 The present work gives decay branching ratios for transitions from the even upper levels 4P1,2,4P3,2, 4Ps,2,2P,j2,2P312, 2D3,2,and 2Df,2in the configurations 5p26s to the odd levels 4S’$2,‘@12,2D$2,2Py,2, and 2P$2 of the configuration 5p3. From the lifetime values given in the literature, transition probabilities are derived and compared with the other values. EXPERIMENTAL
METHOD
In the present work, we used the experimental method that we described in several previously published papers on GeI, PbI, BiI, and AsI.~ To extract individual transition probabilities Aik from the lifetimes 7i = l/CiAii, the decay branching ratios Rik = Aik/CjAij are determined from intensity measurements of the spectrum emitted by a hollow cathode. The lamp is filled either with neon or argon as carrier gas to avoid interferences between the lines of SbI and the carriers. To prevent self-reversal, we used low excitation currents (from 6 to 10 mA). The spectrum is recorded on a 1 m Romand-Vodar monochromator and a 3.4 m Ebert-Fastie spectrometer. To measure the ratio of intensities between neighbouring lines at 259.8 nm (4P51r2D$2,2P,,2-2D$2, and a separation of about 5 pm), we had to use a Fabry-Perot interferometer. The accuracy of the calibration (deuterium lamp and tungsten ribbon lamp) and the stability of the hollow cathode lamps lead us to estimate the error to be about 8% for the branching ratios. However, the error may be larger for the weakest branches (up to 25%). RESULTS
AND DISCUSSION
In Table 1, the branching ratios are given below the wavelengths (in nm) of the transitions. The symbol “-” in the table means that the line was not observed in the spectrum. For antimony, lifetimes have been measured using the Hanle method of Belin et al.,5 the beam-foil technique of Andersen et al.,6 and the delayed coincidence technique of Osherovich and Tezikove7 These values are given in Table 2 and are expressed in ns. In the transitionprobability determinations we used the weighted means given on the lowest line, with allowance for errors estimated given by different authors. Our results (transition probabilities and oscillator strengths) appear in Table 3 and are compared with the theoretical values of Holmgren? which were calculated by using the optimized Hartree-Fock-Slater method. The agreement is quite good but there are some discrepancies for the weakest lines. The experimental values in the present work are often between the two theoretical results obtained, respectively, with the dipole-velocity (DV) approximation and the dipole-length (DL) approximation. However, the agreement is generally better with the results of the dipole-length (DL) approximation. For the ‘Pl12 level, the values of Aik for the two strongest lines we obtained are much lower even than the value obtained from the DV approximation. We, therefore, expect a correspondingly lower value for the lifetime of the 2P1,2level. To check this 133
134
Y. GUERN
and J.
LOTRJAN
Table I. Values of branching ratios (lower line) and wavelengths (upper line) for transitions in nm. -lower
level: 5P3
4s” 3/Z
upper
4P
level: 5~~6s
l/2
43249 4
‘312
45945 4
‘5f2
48332
20 D3/2
’
0
8512
2D0 512
’ cm-l
9854
’ cm-’
2Po l/2 16385
’ cm-’
2P0 312 18464
’
231.2
287.8
372.3
403.4
cm-’
0.793
0.200
0.0041
0.003
’
217.6
267.1
277.0
338.4
363.8
cm-’
0.857
0.041
0.086
0.007
0.009
’
206.9
251.1
cm _*
0.890
259.8
334.6
0.103
0.006
’ cm
-I
2 p1/2 46991
’
212.8
259.8
326.8
cm -1
0.039
0.778
0.183
350.5
2 ‘3/Z 49391 2
D3/2
’
202.4
244.6
252.9
303.3
323.3
cm _,
0.028
0.026
0.726
0.094
0.126
’
181.0
214.0
220.3
257.4
271.9
cm-’
0.151
0.644
0.007
0.068
0.131
2D5,2
’
179.4
5572%
cm-’
55233
211.7
217.9
268.3
0.015
0.908
0.076
hypothesis, we determined a new lifetime value for this level by comparing the lifetimes of two levels on the assumption that the population of SbI levels are in statistical equilibrium. For the two levels identified by the subscripts 1 and 2,
T,,T2
=
81 exp g2
exp
(-NkTGi4ih2i (-EZ/WZjZ*jAlj’
A
E, 45
50
55
l
10bll-’
Fig. I. Determination of the excitation temperature from a plot of In (liiAijlgiAii)vs Ei.
135
Emission measurements for the system 5p3-Sp*6s of neutral antimony Table 2. Values of lifetimes in ns. Levels
4P
(5p26s)
ANDERSEN
4
4 112
5.0 +
p3/2 0.4
2 '512
2 PI/2
4.9 +
0.5
4.8 + 0.4
5.1 +
0.6
4.8 + 0.4
4.6 +
0.5
5.5 + 0.7
2 '3/Z
2 n5/2
%2
4.0
+ 0.3
4.3
+ 0.4
3.7 +
0.4
3.8 +
0.3
6
et al. BELIN
5
et al. OSRBROVICH TEZIKOV'I and
I
4.3 -+ 0.4
used
I
4.1
I
4.9
I
4.9
5.2 + 0.5
1
5.2
1
4.1
1
3.7
)
3.8
The excitation temperature (about 8200 K) was determined by plotting In (liiAij/giAij)vs Ej (Fig. 1) for all of the levels except the 2PI,2level. We obtained a straight line with a correlation coefficient of 0.91. The estimated lifetime of the 2P1,2level is 3.7 + 0.7 ns. The point obtained from the value 5.2 ns for the 2Pl,2 lifetime by Osherovich and Tezikov’ is much higher than our value. We expect a lifetime 7 near 3.7 ns. The new values of Aik and f are identified in Table 3 with asterisks. Table 3. Values of transition nrobabilities and oscillator strentihs. The numbers in oarentheses represent powers . of 10: DV =Adipole-velocityapproximation; DL = dipole-length approximation. Aik
Level
(s-‘1,
Aik
z.
l/2 ' 4.7
4p3/2 z-
'
4.9
4 '512 z-
'
4.9
2 pl/2 z-
5.2
r+-
3.7
'
'3/Z z-
z-
983(5)
201(6)
0.068
287.8
424(5)
315(5)
423(5)
0.027
372.3
863(3)
261(4)
llZ(4)
0.002
403.4
637(3)
633(3)
478(3)
0.001
217.6
175(6)
957(5)
193(6)
0.124
267.1
837(4)
334(4)
839(4)
0.009
277.0
176(6)
124(5)
182(5)
0.013
338.4
l42(4)
791(3)
734(3)
0.005
363.8
175(4)
241(4)
139(4)
0.003
206.9
181(6)
952(5)
188(6)
0.174
373(3)
239(3)
259.8
ZlO(5)
167(5)
329(5)
0.021
334.6
128(3)
lOZ(3)
117(l)
0.003
746(4)
105(5
291(4)
142(5)
0.003
0.004*
259.8
150(6)
Zll(6
218(6)
311(6)
0.076
0.107
325(5)
495(5
0.056
0.079
492(5)
479(5)
__
158(4)
734(3)
'
202.4
683(4)
323(3)
433(4)
244.6
630(4)
138(5)
Zll(5)
0.006
252.9
177(6)
183(6)
279(6)
0.113
303.0
230(5)
364(5)
422(5)
0.063
323.3
307(5)
400(5)
379(5)
0.048
'
3.7
7
z-
3.8
'
0.004
181.0
408(5)
ll8(4)
527(4)
0.020
214.0
174(6)
760(5)
152(6)
0.119
220.3
l79(4)
613(4)
400(4)
0.001
257.4
181(5)
ll9(5)
l90(5)
0.036
271.9
354(5)
105(6)
152(6)
0 039
179.4 2D5/2
LVOVi
0.041
212.8
350.5
4.1
2D3/2
169(6)
251.1
work
J_
231.2
326.8
2
DL
f,
f, present
Dv 4P
(s-‘1,
work
present
510(4)
139(5)
211.7
402(4)
303(5)
463(5)
0.004
217.9
239(6)
ll7(6)
223(6)
0.170
268.3
201(5)
240(5)
339(5)
-
0.032
136
Y. GUERN and J. LOTRIAN
The weaker value of 0.041 for the oscillator strength obtained by Lvov2 for the 231.2 nm line may be explained by the possible presence of Sbz molecules in the vapor of his graphite cell. We also note that the higher ratio f(217.6)/f(231.2) = 2.46 was obtained by Muradov and Muradova* instead of the value 1.82 obtained in the present work. REFERENCES 1. C. H. Corliss and W. E. Bozman, Monograph No. 52 N.B.S., Washington DC. (1%2). 2. B. V. Lvov, Op!. Spectrosc. (USSR) 10, 15 (1965). 3. L. Holmgren, Physica Scripta 11, 15 (1975). 4. J. Lotrian, Y. Guern, J. Cariou, and A. Johannin-Gilles, J. Phys. B 11, 2273 (1978); Y. Guern, J. Lotrian, A. Bideau-Mehu, and A. Johannin-Gilles, 1. Phys. B 11, 3821 (1978);J. Lotrian, Y. Guern, J. Cariou, and A. JohanninGilles, lQSRT 21, 143(1979);J. Lotrian, Y. Guern, and J. Cariou, J. Phys. B 13,685 (1980). 5. G. Belin, S. Garpman, L. Holmgren, and S. Rydbcrg, Physica Scripta 9,213 (1974). 6. T. Andersen, S. Worre-Jgrgensen, and G. Serensen, J. Opt. Sot. Am. 64,891 (1974). 7. A. L. Osherovich and V. V. Tezikov, Opt. Spectrosc. 43,612 (1977). 8. V. G. Muradov and 0. N. Muradova, Zh. Prikl. Spektr. 29,599 (1978).