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Hot-band spectrum of N2O near 589 cm−1
JOURNAL
OF MOLECULAR
SPECTROSCOPY
154,2 18-222 ( 1992)
NOTES Hot-Band Spectrum of N20 near 589 cm-’ The high-resolution infrared spectrum of NzO in the ~2 region near 589 cm _’ has been extensively studied and commonly used as a wavenumber calibration standard (1-4). The strongest hot bands 0 2” 0 + 0 1 ’ 0 and 0 22 0 + 0 1’ 0 in this spectral region are useful as secondary calibration standards (2) for highresolution spectrometers and tunable laser devices. The hot bands have been measured by Jolma et ul. (I) with a spectral resolution of about 0.005 cm-‘, using a Fourier transform spectrometer. Their work which includes the measurement of the vz fundamental and other accompanying hot bands, gives accurate effective rotational constants of N20 in this spectral region. In the course of recording the spectra of the vz fundamental of NzO for calibration standard studies (4) wefoundthattheO2”0+0 l’OandO2*0 +- 0 I ’ 0 hot bands were present with sufficient intensity for an accurate analysis. The increased resolution and sensitivity of the Fourier transform spectrometer have made this possible. Figure 1 shows the Q-branch structure of the 0 2’ 0 +- 0 1 I 0 transition. The wellresolved lines ofthe Q branch allowed us to include them in the rotational analysis. Because the wavenumber measurements of the hot bands were determined with high precision, it is of interest to report them and make a comparison with those existing in the literature. The present work is a continuation of our interests in making accurate measurements on hot bands (5,6) which are useful as secondary wavenumber standards. The infrared spectrum was recorded on a modified Bomem DA3.002 Fourier transform spectrometer ( 7) at the Herzberg Institute of Astrophysics, Ottawa. Using the maximum optical path difference of about 454 cm, an unapodized resolution of about 0.00 14 cm-i was possible. A helium-cooled Cu:Ge detector was used. Cooled filters served to limit the bandwidth to the 500-700 cm-’ range. With a total co-adding time of about 20 h. a signal-to-noise ratio greater than 200: 1 was obtained. A partial pressure of 75 mTorr of N20 at an absorption pathlength of 2 m was sufficient in providing satisfactory line intensities for wavenumber determinations. The spectrum of the hot bands was calibrated using the wavenumbers of the Y?fundamental of CO1 near 667 cm-‘, which were recorded at the same time that the N20 lines were recorded. The CO2 calibration wavenumbers with an absolute accuracy of about 0.00006 cm-’ were taken from a recent calibration standards study conducted by Johns et al. (4). The absolute accuracy of measured lines is estimated to be about *O.OOOOS cm-‘. In the analysis of the spectra. the rotational energy level is represented by F(J)
= B[J(J
+
1) - P] - D[J(J + 1) - i’y + H[J(J + 1) - P13.
When 1 is greater than zero, the l-type doubling kO.5
t1 / FIG. 0022-2852192
was taken into consideration
by an additional
{ q&J + 1 ) - q&P(J + I )’ + q,,P(J + 1131.
I 579.25
I
I 579.30
CM -’
579.35 J
1. FTIR spectrum of the Q branch of the 0 2’ 0 + 0 1’ 0 Band of NzO.
$5.00
Copyright c 1992 by Academic Preys, Inc All rights of reproduction in any form reserved
218
term
TABLE I Results (in cm-‘) Obtained from the Analysis of the 0 2’ 0 +- 0 1' 0 Band of N20
constant
Present
578.945
“0
Work
146(11)
Literature
( Ref.
578.945
40(5).?
578.944
61(5)d=
2 )
B"
0.419
572 97(27)
0.419 0.419
177 55(3)c 969 50(7)d
D" x lo6
0.178
16(M)
0.178 0.179
49(2)C 49(4)d
H" x 1O1'
-0.399(55)
o.oc O.Od
AB x lo3
0.344
635(81)
AD x lo7
0.654
3(14)
AH x 10
12
0.743 -0.048 0.710 0.700
32(3O)c 63(34)d O(32)c O(34)d
0.624(71)
3.08(9)c 3.08(9)d
s; x lo3
0.791
933(41)
0.791
954(67)
s; x lo8
0.100
6(42)
0.099
5(18)
Std.
0.000
039
0.000
149
dev.
No. of lines
a Values
85
are modified
69
for model
differences
in fitting.
TABLE II Results (in cm-‘) Obtained from the Analysis of the 0 2’ 0 + 0 I ’ 0 Band of N20
constant
Present
590.237
“0
Work
607(14)
Literature
( Ref.
590.238
lO(5)Z
590.237
32(3)da
2 )
B"
0.419
572 97(27)
0.419 0.419
177 55(3)c 969 50(7)d
D" x lo6
0.178
16(1&l)
0.178 0.179
49(2)c 49(4)d
AB x lo3
0.551
025(92)
0.946 0.155
90(3O)c 25(22)d
AD
10'
-0.283
7(15)
-0.585 0.022
AH x.10"
-0.177
8(70)
-O.Z97(Ez)c O.Od
q;
x
l(3O)C 3(12)d
lo3
0.791
933(41)
0.791
954(67)
9;; x lo8
0.100
6 (42)
0.099
5(M)
4; x lo5
-0.164
x lo7
0.566
49
0.000
059
0.000 0.000
15oc 089d
g;
x
Std.
dev.
of lines
NO.
a Values
4(46) (45)
137
159
are modified
for model
differences
in fitting.
220
NOTES
Since both hot bands have the same lower vibrational were fitted simultaneously to obtain effective rotational
state (0 I ’ 0), all the assigned lines of both bands constants using the following expression:
v(/) = “0 + F’(Y)
- F”(Y).
Lines which are badly blended or weak in the observed spectrum, were excluded from the polynomial leastsquares fit. We found that the inclusion of the constant H for the 0 2’ 0 and 0 22 0 vibrational states would improve the rms deviation of the fitted lines. Consequently, the constant H for the states was included in the final fit. The results of the hot bands derived from the unconstrained fit are presented in Tables 1 and II. The upper state constants are expressed in the form B” + AB, D” + AD, and H” + AH. Values of AB, AD and AH are given in both tables. For comparison purposes, the results of Jolma et al. (2) are included. In their analysis, the c (or e) levels and the d (orf‘) levels of the l-type doubling were fitted separately. resulting in slight differences between their molecular constants and those of the present study. Their band origins given in Tables I and II were modified according to the term value equation we used in the present fit for the purpose of comparison. The I-type doubling constants ( qBand qo) for the 0 2’ 0 vibrational state are given in Table II. These values were not given in Ref. (2). It is worth mentioning that the Q-branch lines of both hot bands are included in our analysis. The agreement of the present results with those of Jolma el u/. (2) is good. Generally, the molecular constants for the 0 I ’ 0 state agree satisfactorily with those existing in the literature (1. 3. 8. 9). With an rms standard deviation of about 0.00004 cm-’ to 0.00006 cm-’ for all the lines fitted, our present measurements may serve as an alternative calibration standard to the u2 fundamental of NZO. The observed wavenumbers. with their residuals (O-C). of 0 2’ 0 + 0 I i 0 and of 0 2’ 0 +- 0 I ’ 0 bands are given in Table III and Table IV, respectively.
TABLE III Observed J 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
Line Positions
Pee(J)
o-c
577.689482
566.944341 566.127816 565.312616 564.498855 563.686335 562.875153 562.065119 561.256531 560.449012 559.642624
-14 -2 10 47 21 -12 -1 44 -22 -9 59 -67 -10 -8 -11 -50 12 -3 28 -62 54 25 -56
558.033512 557.230490 556.428651 555.627764 554.827819 554.028851
22 -51 9 9 -25 -17
576.854112 576.020230 575.187860 574.356914 573.527442 572.699492 571.873045 571.047950 570.224385 569.402316 568.581480 567.762239
(in cm-‘)
of the 0 2” 0 + 0 1 ’ 0 Band of N20
Qef(J)
o-c
nee(J)
582.732940
583.578500 584.425631 585.274174 586.124136 586.975482 587.828177 588.682235 589.537589 590.394286 591.252230 592.111556 579.348635 579.345904 579.342856 579.339472 579.335752 579.331604 579.327031 579.321995 579.316482
52 35 15 -1 15 0 -12 -27 -27
579.303815 579.296682 579.288760 579.280242 579.270940 579.260965 579.250155 579.238426 579.225841 579.212374
-47 28 -45 -32 -79 -31 -7 -44 -31 54
579.197829
579.182194 579.165448
x3 16
593.833593
594.696475 595.560413 596.425489 597.291584 598.158732 599.026880 599.896021 600.765996 601.636795 602.508428 603.380966 604.254171 605.128026 606.002529 606.877615 607.753203 608.629404 609.505869 610.382705 611.259838 612.137194
o-c
69
-52 -37 -32 -13 0 -9 -5 -35 -27 -54 46 -22 42 27 49 24 23 33 84 61 -6 -60 13 24 4 0 -1 -27 85 44 11 -28 -90
221
NOTES TABLE IV Observed
Line Positions
Pee(J)
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 J
o-c
583.148394 582.323515 581.500574 580.679675 579.860733 579.043729 578.228869 577.416035 576.605271 575.796692 574.990182 574.185927 573.383736 572.583684 571.785927 570.990432 570.197224 569.406319 568.617841 567.831696 567.048026
18 19 -12 17 2 -93 -79 -97 -122 -62 -57 53 53 -12 -12 -10 -13 -36 13 6 50
565.488001 564.711765
39 28
Qfe(J)
o-c
10
11 12 13 14 15 16 17 18 19 20 21 22 23 24
of the 0 2* 0 + 0 I ’ 0 Band of NzO
(in cm-‘) o-c
Pff(J)
583.103859 582.266229 581.428925 580.591916 579.755391 578.919199 578.083282 577 247826 576.412669 575.577833 574.743437 573.909525 573.075957 572.242650 571.409789 570.577346 569.745268 568.913721 568.082402 567.251654 566.421181 565.591108 564.761467 563.932206 563.103270 562.274822
Qef(J)
-21 -8 -14 -75 -5 40 -2 50 32 -39 -48 45 98 23 3 7 -20 84 16 116 87 53 46 13 -99 -127
o-c
588.994470 -117 589.002443 -38 589.149123 69 589.175536 -30 589.203994 25 589.234322 60 589.266482 38 589.300524 9 589.336446 -25 589.374273 -40 589.414093 56 589.455590 -52 589.499087 -38 589.544332 -151
589.012011 -42 589.023377 -69 589.036816 -9 589.052342 -29 589.061024 4 589.070259 -29 589.080182 -21 589.090756 -37
Ree(J) 591.503174 592.348972 593.196788 594.046621 594.898176 595.751646 596.607115 597.464464 598.323877 599.184991 600.048264 600.913345 601.780463 602.649595 603.520651 604.393800 605.269005 606.146237 607.025598 607.906950 608.790599 609.676313 610.564202 611.454304 612.346622 613.241204 614.138110 615.037329 615.938916 617.749320 618.658218
J
25 26 27 28 29 30 31 33 34 35 36 37 38 39 40
Qfe(J)
o-c
o-c
Rff(J)
58 -75 -82 31 -34 -88 -54 -60 71 -36 66 14 22 52 -2 11 35 21 51 -36 43 32 15 6 -21 -46 -36 -34 -14
591.498329 592.339523 593.180996 594.022618 594.864732 595.707098 596.549697 597.392481 598.235619 599.079026 599.922675
-13 27 52 -64 27 90 109 41 59 82 89
601.610764 602.455111 603.299579 604.144632 604.989723 605.834944 606.680379 607.526210 608.372073 609.218311 610.064545 610.911096 611.757917 612.604830 613.451776 614.298946 615.146352 615.993850
135 91 -72 115 110 12 -91 -9 -102 -20 -134 -116 -6 27 -68 -91 -20
80 171
o-c
589.591781 68 589.640708 -104 589.691775 0 589.744572 -26 589.799235 -42 589.855820 16 589.914169 -6 590.100285 6 590.165946 -4 590.233394 -30 590.302663 -28 590.373727 -12
11
617.689194 70 618.537024 105 619.384939 141 Q,__(J)
o-c
589.102033 589.114181
-57 58
589.140561 589.155020
31 51
589.186519 589.221834 589.240981 589.261116
24 46 41 -31
589.282329 589.304817 589.328458 589.353291 589.379378
-118 -63 -29 -16 -3
ACKNOWLEDGMENTS The authors are grateful to Dr. J. W. C. Johns for giving them the opportunity to record the spectrum used in this work. One of us (T.L.T.) thanks him for his hospitality and guidance during his visit at the Herzberg Institute of Astrophysics, Ottawa.
REFERENCES I. M. J. REISFELD AND H. FLICKER, Appl. Opt. 18, 1136-1138 ( 1979). 2. K. JOLMA, J. KAUPPINEN. AND V.-M. HORNEMAN, J. MO/. Specrrosc
101, 278-284
(1983)
222 3. 4. 5. 6. 7. 8. 9.
M. D. VANEK, M. SCHNEIDER,J. S. WELLS, ANDA. G. MAKI, J. Mol. Spectrosc. 134, 154-158 ( 1989). J. W. C. JOHNS, M. NOEL, AND T. L. TAN, to be submitted for publication. T. L. TAN, E. C. Loor, AND K. T. LUA, J. Mol. Spectrosc. 148, 265-269 ( 1991 ). T. L. TAN ANDE. C. LOOI, .I. Mol. Spectrosc. 148,262-264 ( 1991). J. W. C. JOHNS, Mikrochim. Acta [ Wien] III, 171-188 (1987). J. S. WELLS, A. HINZ, AND A. G. MAKI, J. Mol. Specfrosc. 114, 84-96 ( I985 ). M. D. VANEK, D. A. JENNINGS,J. S. WELLS, ANDA. G. MAKI, J. Mol. Spectrosc. 138, 79-83 (1989). T. L. TAN E. C. LOOI K. T. LUA
Department ofPhysics, Faculty qf Science National University of Singapore Lower Kent Ridge Road Singapore 051 I, Singapore Received November 20. 1991
OF MOLECULAR
SPECTROSCOPY
154,2 18-222 ( 1992)
NOTES Hot-Band Spectrum of N20 near 589 cm-’ The high-resolution infrared spectrum of NzO in the ~2 region near 589 cm _’ has been extensively studied and commonly used as a wavenumber calibration standard (1-4). The strongest hot bands 0 2” 0 + 0 1 ’ 0 and 0 22 0 + 0 1’ 0 in this spectral region are useful as secondary calibration standards (2) for highresolution spectrometers and tunable laser devices. The hot bands have been measured by Jolma et ul. (I) with a spectral resolution of about 0.005 cm-‘, using a Fourier transform spectrometer. Their work which includes the measurement of the vz fundamental and other accompanying hot bands, gives accurate effective rotational constants of N20 in this spectral region. In the course of recording the spectra of the vz fundamental of NzO for calibration standard studies (4) wefoundthattheO2”0+0 l’OandO2*0 +- 0 I ’ 0 hot bands were present with sufficient intensity for an accurate analysis. The increased resolution and sensitivity of the Fourier transform spectrometer have made this possible. Figure 1 shows the Q-branch structure of the 0 2’ 0 +- 0 1 I 0 transition. The wellresolved lines ofthe Q branch allowed us to include them in the rotational analysis. Because the wavenumber measurements of the hot bands were determined with high precision, it is of interest to report them and make a comparison with those existing in the literature. The present work is a continuation of our interests in making accurate measurements on hot bands (5,6) which are useful as secondary wavenumber standards. The infrared spectrum was recorded on a modified Bomem DA3.002 Fourier transform spectrometer ( 7) at the Herzberg Institute of Astrophysics, Ottawa. Using the maximum optical path difference of about 454 cm, an unapodized resolution of about 0.00 14 cm-i was possible. A helium-cooled Cu:Ge detector was used. Cooled filters served to limit the bandwidth to the 500-700 cm-’ range. With a total co-adding time of about 20 h. a signal-to-noise ratio greater than 200: 1 was obtained. A partial pressure of 75 mTorr of N20 at an absorption pathlength of 2 m was sufficient in providing satisfactory line intensities for wavenumber determinations. The spectrum of the hot bands was calibrated using the wavenumbers of the Y?fundamental of CO1 near 667 cm-‘, which were recorded at the same time that the N20 lines were recorded. The CO2 calibration wavenumbers with an absolute accuracy of about 0.00006 cm-’ were taken from a recent calibration standards study conducted by Johns et al. (4). The absolute accuracy of measured lines is estimated to be about *O.OOOOS cm-‘. In the analysis of the spectra. the rotational energy level is represented by F(J)
= B[J(J
+
1) - P] - D[J(J + 1) - i’y + H[J(J + 1) - P13.
When 1 is greater than zero, the l-type doubling kO.5
t1 / FIG. 0022-2852192
was taken into consideration
by an additional
{ q&J + 1 ) - q&P(J + I )’ + q,,P(J + 1131.
I 579.25
I
I 579.30
CM -’
579.35 J
1. FTIR spectrum of the Q branch of the 0 2’ 0 + 0 1’ 0 Band of NzO.
$5.00
Copyright c 1992 by Academic Preys, Inc All rights of reproduction in any form reserved
218
term
TABLE I Results (in cm-‘) Obtained from the Analysis of the 0 2’ 0 +- 0 1' 0 Band of N20
constant
Present
578.945
“0
Work
146(11)
Literature
( Ref.
578.945
40(5).?
578.944
61(5)d=
2 )
B"
0.419
572 97(27)
0.419 0.419
177 55(3)c 969 50(7)d
D" x lo6
0.178
16(M)
0.178 0.179
49(2)C 49(4)d
H" x 1O1'
-0.399(55)
o.oc O.Od
AB x lo3
0.344
635(81)
AD x lo7
0.654
3(14)
AH x 10
12
0.743 -0.048 0.710 0.700
32(3O)c 63(34)d O(32)c O(34)d
0.624(71)
3.08(9)c 3.08(9)d
s; x lo3
0.791
933(41)
0.791
954(67)
s; x lo8
0.100
6(42)
0.099
5(18)
Std.
0.000
039
0.000
149
dev.
No. of lines
a Values
85
are modified
69
for model
differences
in fitting.
TABLE II Results (in cm-‘) Obtained from the Analysis of the 0 2’ 0 + 0 I ’ 0 Band of N20
constant
Present
590.237
“0
Work
607(14)
Literature
( Ref.
590.238
lO(5)Z
590.237
32(3)da
2 )
B"
0.419
572 97(27)
0.419 0.419
177 55(3)c 969 50(7)d
D" x lo6
0.178
16(1&l)
0.178 0.179
49(2)c 49(4)d
AB x lo3
0.551
025(92)
0.946 0.155
90(3O)c 25(22)d
AD
10'
-0.283
7(15)
-0.585 0.022
AH x.10"
-0.177
8(70)
-O.Z97(Ez)c O.Od
q;
x
l(3O)C 3(12)d
lo3
0.791
933(41)
0.791
954(67)
9;; x lo8
0.100
6 (42)
0.099
5(M)
4; x lo5
-0.164
x lo7
0.566
49
0.000
059
0.000 0.000
15oc 089d
g;
x
Std.
dev.
of lines
NO.
a Values
4(46) (45)
137
159
are modified
for model
differences
in fitting.
220
NOTES
Since both hot bands have the same lower vibrational were fitted simultaneously to obtain effective rotational
state (0 I ’ 0), all the assigned lines of both bands constants using the following expression:
v(/) = “0 + F’(Y)
- F”(Y).
Lines which are badly blended or weak in the observed spectrum, were excluded from the polynomial leastsquares fit. We found that the inclusion of the constant H for the 0 2’ 0 and 0 22 0 vibrational states would improve the rms deviation of the fitted lines. Consequently, the constant H for the states was included in the final fit. The results of the hot bands derived from the unconstrained fit are presented in Tables 1 and II. The upper state constants are expressed in the form B” + AB, D” + AD, and H” + AH. Values of AB, AD and AH are given in both tables. For comparison purposes, the results of Jolma et al. (2) are included. In their analysis, the c (or e) levels and the d (orf‘) levels of the l-type doubling were fitted separately. resulting in slight differences between their molecular constants and those of the present study. Their band origins given in Tables I and II were modified according to the term value equation we used in the present fit for the purpose of comparison. The I-type doubling constants ( qBand qo) for the 0 2’ 0 vibrational state are given in Table II. These values were not given in Ref. (2). It is worth mentioning that the Q-branch lines of both hot bands are included in our analysis. The agreement of the present results with those of Jolma el u/. (2) is good. Generally, the molecular constants for the 0 I ’ 0 state agree satisfactorily with those existing in the literature (1. 3. 8. 9). With an rms standard deviation of about 0.00004 cm-’ to 0.00006 cm-’ for all the lines fitted, our present measurements may serve as an alternative calibration standard to the u2 fundamental of NZO. The observed wavenumbers. with their residuals (O-C). of 0 2’ 0 + 0 I i 0 and of 0 2’ 0 +- 0 I ’ 0 bands are given in Table III and Table IV, respectively.
TABLE III Observed J 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
Line Positions
Pee(J)
o-c
577.689482
566.944341 566.127816 565.312616 564.498855 563.686335 562.875153 562.065119 561.256531 560.449012 559.642624
-14 -2 10 47 21 -12 -1 44 -22 -9 59 -67 -10 -8 -11 -50 12 -3 28 -62 54 25 -56
558.033512 557.230490 556.428651 555.627764 554.827819 554.028851
22 -51 9 9 -25 -17
576.854112 576.020230 575.187860 574.356914 573.527442 572.699492 571.873045 571.047950 570.224385 569.402316 568.581480 567.762239
(in cm-‘)
of the 0 2” 0 + 0 1 ’ 0 Band of N20
Qef(J)
o-c
nee(J)
582.732940
583.578500 584.425631 585.274174 586.124136 586.975482 587.828177 588.682235 589.537589 590.394286 591.252230 592.111556 579.348635 579.345904 579.342856 579.339472 579.335752 579.331604 579.327031 579.321995 579.316482
52 35 15 -1 15 0 -12 -27 -27
579.303815 579.296682 579.288760 579.280242 579.270940 579.260965 579.250155 579.238426 579.225841 579.212374
-47 28 -45 -32 -79 -31 -7 -44 -31 54
579.197829
579.182194 579.165448
x3 16
593.833593
594.696475 595.560413 596.425489 597.291584 598.158732 599.026880 599.896021 600.765996 601.636795 602.508428 603.380966 604.254171 605.128026 606.002529 606.877615 607.753203 608.629404 609.505869 610.382705 611.259838 612.137194
o-c
69
-52 -37 -32 -13 0 -9 -5 -35 -27 -54 46 -22 42 27 49 24 23 33 84 61 -6 -60 13 24 4 0 -1 -27 85 44 11 -28 -90
221
NOTES TABLE IV Observed
Line Positions
Pee(J)
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 J
o-c
583.148394 582.323515 581.500574 580.679675 579.860733 579.043729 578.228869 577.416035 576.605271 575.796692 574.990182 574.185927 573.383736 572.583684 571.785927 570.990432 570.197224 569.406319 568.617841 567.831696 567.048026
18 19 -12 17 2 -93 -79 -97 -122 -62 -57 53 53 -12 -12 -10 -13 -36 13 6 50
565.488001 564.711765
39 28
Qfe(J)
o-c
10
11 12 13 14 15 16 17 18 19 20 21 22 23 24
of the 0 2* 0 + 0 I ’ 0 Band of NzO
(in cm-‘) o-c
Pff(J)
583.103859 582.266229 581.428925 580.591916 579.755391 578.919199 578.083282 577 247826 576.412669 575.577833 574.743437 573.909525 573.075957 572.242650 571.409789 570.577346 569.745268 568.913721 568.082402 567.251654 566.421181 565.591108 564.761467 563.932206 563.103270 562.274822
Qef(J)
-21 -8 -14 -75 -5 40 -2 50 32 -39 -48 45 98 23 3 7 -20 84 16 116 87 53 46 13 -99 -127
o-c
588.994470 -117 589.002443 -38 589.149123 69 589.175536 -30 589.203994 25 589.234322 60 589.266482 38 589.300524 9 589.336446 -25 589.374273 -40 589.414093 56 589.455590 -52 589.499087 -38 589.544332 -151
589.012011 -42 589.023377 -69 589.036816 -9 589.052342 -29 589.061024 4 589.070259 -29 589.080182 -21 589.090756 -37
Ree(J) 591.503174 592.348972 593.196788 594.046621 594.898176 595.751646 596.607115 597.464464 598.323877 599.184991 600.048264 600.913345 601.780463 602.649595 603.520651 604.393800 605.269005 606.146237 607.025598 607.906950 608.790599 609.676313 610.564202 611.454304 612.346622 613.241204 614.138110 615.037329 615.938916 617.749320 618.658218
J
25 26 27 28 29 30 31 33 34 35 36 37 38 39 40
Qfe(J)
o-c
o-c
Rff(J)
58 -75 -82 31 -34 -88 -54 -60 71 -36 66 14 22 52 -2 11 35 21 51 -36 43 32 15 6 -21 -46 -36 -34 -14
591.498329 592.339523 593.180996 594.022618 594.864732 595.707098 596.549697 597.392481 598.235619 599.079026 599.922675
-13 27 52 -64 27 90 109 41 59 82 89
601.610764 602.455111 603.299579 604.144632 604.989723 605.834944 606.680379 607.526210 608.372073 609.218311 610.064545 610.911096 611.757917 612.604830 613.451776 614.298946 615.146352 615.993850
135 91 -72 115 110 12 -91 -9 -102 -20 -134 -116 -6 27 -68 -91 -20
80 171
o-c
589.591781 68 589.640708 -104 589.691775 0 589.744572 -26 589.799235 -42 589.855820 16 589.914169 -6 590.100285 6 590.165946 -4 590.233394 -30 590.302663 -28 590.373727 -12
11
617.689194 70 618.537024 105 619.384939 141 Q,__(J)
o-c
589.102033 589.114181
-57 58
589.140561 589.155020
31 51
589.186519 589.221834 589.240981 589.261116
24 46 41 -31
589.282329 589.304817 589.328458 589.353291 589.379378
-118 -63 -29 -16 -3
ACKNOWLEDGMENTS The authors are grateful to Dr. J. W. C. Johns for giving them the opportunity to record the spectrum used in this work. One of us (T.L.T.) thanks him for his hospitality and guidance during his visit at the Herzberg Institute of Astrophysics, Ottawa.
REFERENCES I. M. J. REISFELD AND H. FLICKER, Appl. Opt. 18, 1136-1138 ( 1979). 2. K. JOLMA, J. KAUPPINEN. AND V.-M. HORNEMAN, J. MO/. Specrrosc
101, 278-284
(1983)
222 3. 4. 5. 6. 7. 8. 9.
M. D. VANEK, M. SCHNEIDER,J. S. WELLS, ANDA. G. MAKI, J. Mol. Spectrosc. 134, 154-158 ( 1989). J. W. C. JOHNS, M. NOEL, AND T. L. TAN, to be submitted for publication. T. L. TAN, E. C. Loor, AND K. T. LUA, J. Mol. Spectrosc. 148, 265-269 ( 1991 ). T. L. TAN ANDE. C. LOOI, .I. Mol. Spectrosc. 148,262-264 ( 1991). J. W. C. JOHNS, Mikrochim. Acta [ Wien] III, 171-188 (1987). J. S. WELLS, A. HINZ, AND A. G. MAKI, J. Mol. Specfrosc. 114, 84-96 ( I985 ). M. D. VANEK, D. A. JENNINGS,J. S. WELLS, ANDA. G. MAKI, J. Mol. Spectrosc. 138, 79-83 (1989). T. L. TAN E. C. LOOI K. T. LUA
Department ofPhysics, Faculty qf Science National University of Singapore Lower Kent Ridge Road Singapore 051 I, Singapore Received November 20. 1991