V. Malathy Devi, D. Chris Benner, Mary Ann H. Smith, and Curtis P. Rinsland, "Measurements of air-, N2-, and O2-broadened halfwidths and pressure-induced line shifts in the ν3 band of 13CH4," Appl. Opt. 30, 287-304 (1991)
Air-, nitrogen-, and oxygen-broadened halfwidth and pressure-induced line shift coefficients have been measured for over seventy-five individual vibration–rotation transitions in the ν3 fundamental band of 13CH4 at 3 μm from room temperature IR laboratory absorption spectra recorded at a 0.01-cm−1 resolution with a Fourier transform spectrometer. Transitions up to J″ = 13 in the P-branch and J″ = 7 in the R-branch were analyzed using a nonlinear least-squares curve fitting technique assuming a Voigt line shape. From the analysis, we have determined the mean ratios of air- to nitrogen-broadened and air- to oxygen-broadened halfwidth coefficients obtained for the same transitions as 1.00 ± 0.03 and 1.06 ± 0.04, respectively. The measured pressure shift coefficients were predominantly negative, and the mean and standard deviation values for air-, nitrogen-, and oxygen-broadened shifts were −0.0067 ± 0.0032, −0.0068 ± 0.0041, and −0.0066 ± 0.0028 cm−1 atm−1, respectively. Comparisons are made with the results obtained for similar transitions in the ν3 band of 12CH4 and the ν4 band of 13CH4.
V. Malathy Devi, D. Chris Benner, Mary Ann H. Smith, and Curtis P. Rinsland, "Measurements of air-, N2-, and O2-broadened halfwidths and pressure-induced line shifts in the ν3 band of 13CH4: errata," Appl. Opt. 30, 2928-2928 (1991) https://opg.optica.org/ao/abstract.cfm?uri=ao-30-21-2928
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Halfwidth coefficients are in cm−1 atm−1 at 296 K. Values in parentheses represent 2σ statistical uncertainties in units of the last digit quoted.
1982 AFGL compilation; Ref. 17 and 1986 HITRAN database; Ref. 18
b°L(Air) = 0.79 b°L(N2) + 0.21 b°L(O2)
Tentative assignment (see text)
Table III
Pressure-Induced Line Shift Coefficientsa Measured in the ν3 Band of 13CH4
Pressure shift coefficients are in cm−1 atm−1 at about 298 K. Values in parentheses represent 2σ statistical uncertainties in units of the last digit quoted.
1982 AFGL compilation; Ref. 17 and 1986 HITRAN database; Ref. 18.
Tentative assignment (see text)
Table IV
Comparison of Observed and Calculated Halfwidth Coefficients (cm−1 atm−1) at 296 K for R-Branch Lines in the ν3 Band
Present work. The values in parentheses are 2σ uncertainties in units of the last digit quoted.
Ref. 8. The values reported in this article correspond to the ν3 band of 12CH4. The calculated values given in Ref. (8) are for 300 K. Those values are converted to 296 K for purpose of comparison assuming a T−1.0 temperature dependence for halfwidth coefficients. The air-broadened widths are calculated from the Na and O2-broadened widths using the relation bL° (air) = 0.79 bL° (N2) + 0.21 bL° (O2).
Table V
Comparison of Air-Broadened and Nitrogen-Broadened Halfwidth Coefficientsa In the ν3 Bands of 13CH4 and 12CH4
Halfwidth coefficients are in cm−1 atm−1 at 296 K. Values given in parentheses are 2σ statistical uncertainties in units of the last digit quoted. ν3 band air–broadened halfwidth coefficient in 13CH4 divided by ν3 band air broadened halfwidth coefficient in 12CH4. Numbers in parentheses are 2σ statistical uncertainties in units of the last digit quoted. ν3 band nitrogen–broadened halfwidth coefficient in 13CH4 divided by ν3 band nitrogen–broadened halfwidth coefficient in 12CH4. Numbers in parentheses are 2σ statistical uncertainties in units of the last digit quoted.
Table VI
Mean and Standard Deviation of Measured Halfwidth Coefficients (In cm−1 atm−1 at 296 K) for each |m| Value Obtained from Air, N2, and O2 Broadening Measurements In the ν3 Band of 13CH4
F Species
A Species
E Species
Air
N2
O2
Air
N2
O2
Air
N2
O2
1
0.0586
0.0570
0.0550
2
0.0646 (1)
0.0642 (8)
0.0601 (6)
0.0647
0.0647
0.0605
3
0.0654 (8)
0.0655 (5)
0.0594 (38)
0.0628
0.0611
0.0571
4
0.0626 (12)
0.0624 (25)
0.0581 (39)
0.0636 (39)
0.0615 (47)
0.0550 (70)
0.0635
0.0626
0.0583
5
0.0630 (41)
0.0631 (42)
0.0591 (47)
0.0598
0.0585
0.0520
0.0608
0.0585
0.0560
6
0.0622 (33)
0.0630 (51)
0.0589 (44)
0.0595 (25)
0.0614 (62)
0.0564 (45)
0.0597 (13)
0.0586 (35)
0.0562 (17)
7
0.0619 (40)
0.0611 (32)
0.0572 (33)
0.0603 (5)
0.0589
0.0562
0.0536 (57)
0.0508
0.0475
8
0.0579 (50)
0.0573 (58)
0.0541 (60)
0.0553 (39)
0.0538 (31)
0.0516 (16)
0.0550 (60)
0.0571 (71)
0.0531 (55)
9
0.0566 (59)
0.0576 (62)
0.0544 (45)
0.0524 (17)
0.0540 (33)
0.0502 (13)
0.0525
0.0520
0.0502
10
0.0566 (40)
0.0562 (57)
0.0544 (26)
0.0540 (17)
0.0540 (22)
0.0512 (28)
0.0401
0.0392
0.0394
11
0.0527 (10)
0.0561 (19)
0.0524 (3)
0.0460
0.0438
0.0456
0.0518
0.0476
12
0.0560 (67)
0.0558 (84)
0.0521 (51)
0.0480 (4)
0.0477 (40)
0.0466 (14)
0.0527
0.0492
13
0.0517 (26)
0.0526 (0)
0.0489 (56)
0.0512
0.0486
0.0522
0.0326
0.0308
Tables (6)
Table I
Experimental Conditions
PARAMETER
GAS MIXTURE
PRESSURE (TORR)
PATH (CM)
T(K)
Position (ν)
99% 13CH4
1.05
5
298
99% 13CH4
1.022
25
298
bL°(13CH4–air)
1.0% 13CH4
75.5, 150.4, 300.6,
in dry air
500.3
5
298
0.3–1.0% 13CH4
225.2, 400.15
25
298
in dry air
bL°(13CH4–N2)
0.3–1.0% 13CH4
100.25, 200.25,
in N2
300.55, 400.15
25
298
bL°(13CH4–O2)
0.3–1.0% 13CH4
100.6, 200.3,
in O2
300.5, 400.3
25
298
Table II
Air-, N2-, and O2-Broadened Halfwidthsa (cm−1 atm−1) in the ν3 Band of 13CH4
Halfwidth coefficients are in cm−1 atm−1 at 296 K. Values in parentheses represent 2σ statistical uncertainties in units of the last digit quoted.
1982 AFGL compilation; Ref. 17 and 1986 HITRAN database; Ref. 18
b°L(Air) = 0.79 b°L(N2) + 0.21 b°L(O2)
Tentative assignment (see text)
Table III
Pressure-Induced Line Shift Coefficientsa Measured in the ν3 Band of 13CH4
Pressure shift coefficients are in cm−1 atm−1 at about 298 K. Values in parentheses represent 2σ statistical uncertainties in units of the last digit quoted.
1982 AFGL compilation; Ref. 17 and 1986 HITRAN database; Ref. 18.
Tentative assignment (see text)
Table IV
Comparison of Observed and Calculated Halfwidth Coefficients (cm−1 atm−1) at 296 K for R-Branch Lines in the ν3 Band
Present work. The values in parentheses are 2σ uncertainties in units of the last digit quoted.
Ref. 8. The values reported in this article correspond to the ν3 band of 12CH4. The calculated values given in Ref. (8) are for 300 K. Those values are converted to 296 K for purpose of comparison assuming a T−1.0 temperature dependence for halfwidth coefficients. The air-broadened widths are calculated from the Na and O2-broadened widths using the relation bL° (air) = 0.79 bL° (N2) + 0.21 bL° (O2).
Table V
Comparison of Air-Broadened and Nitrogen-Broadened Halfwidth Coefficientsa In the ν3 Bands of 13CH4 and 12CH4
Halfwidth coefficients are in cm−1 atm−1 at 296 K. Values given in parentheses are 2σ statistical uncertainties in units of the last digit quoted. ν3 band air–broadened halfwidth coefficient in 13CH4 divided by ν3 band air broadened halfwidth coefficient in 12CH4. Numbers in parentheses are 2σ statistical uncertainties in units of the last digit quoted. ν3 band nitrogen–broadened halfwidth coefficient in 13CH4 divided by ν3 band nitrogen–broadened halfwidth coefficient in 12CH4. Numbers in parentheses are 2σ statistical uncertainties in units of the last digit quoted.
Table VI
Mean and Standard Deviation of Measured Halfwidth Coefficients (In cm−1 atm−1 at 296 K) for each |m| Value Obtained from Air, N2, and O2 Broadening Measurements In the ν3 Band of 13CH4
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