ABSORPTION SPECTRA FOR THE 889 nm BAND OF
METHANE DERIVED FROM INTRACAVITY LASER
SPECTROSCOPY MEASUREMENTS MADE AS A
FUNCTION OF LOW SAMPLE TEMPERATURES
SADASIVAN SHAJI and JIM O’BRIEN
Department of Chemistry & Biochemistry and Center for Molecular
Electronics, University of Missouri, St. Louis, MO 63121;
LEAH O’BRIEN
Department of Chemistry, Southern Illinois University,
Edwardsville, IL, 62026-1652
Contents
ILS Overview
ILS setup
Cryogenic Chamber – design and features
Pressure – Temperature profiles and temperature calculated from
pressure change
Determining temperature from rotational populations for 760 nm A
band of oxygen
Methane spectra for 889 nm band at three temperatures: -112, -142
and -174 C.
Absorption coefficients for 889 nm band of methane at low
temperatures
Conclusion
Acknowledgements
Overview
Methane is an important component in the atmospheres of giant planets and their
major satellites
Laboratory spectral data at low temperatures are required to interpret the planetary
data properly
Methane spectrum in near -IR region is intrinsically very weak and hence a very
sensitive method like intracavity laser spectroscopy (ILS) is needed
Absorption lines appear superimposed on the output of the laser which is operated
in a time-modulated fashion
ILS enhances the sensitivity with its tremendous 'effective pathlength' > 100 km
being achieved easily
ILS is both ultrasensitive and quantitative method for acquiring weak absorption
spectra
Tuning
Assembly
HR
FM
Cryogenic fluid
OC
Lens
FM
Ti:sapphire
crystal
Dry Ar
Vacuum
AOM1
To Separate
O2 or CH4 Vacuum
Pumps
He
Solid-State (Verdi)
532 nm Laser
Printer
Computer
Intracavity
Chamber
Detector
Interface
Diode
Spectrograph
Lens Array
Detector
Digital Pulse &
Delay Generator
I2
AOM2
PhotoDiode
Oscilloscope
Schematic diagram for the intracavity laser spectrometer
FM=fold mirror; HR=high reflector;
OC=output coupler; AOM=acousto-optic modulator
Bellows
Coupling
End Plate
Bellows
Coupling
Laser
beam
Brewster Angle
Window Mount
Laser beam
Brewster Angle
Window Mount
Chamber for Sample Gas
Chamber Containing Helium Gas
Vacuum Envelope
Cyrogenic Chamber
Overview of the four walled Cryogenic chamber
End Plate
40.000"
End Plate
End Plate
30.22"
2.25"
2.25"
4.00"
4.00"
Bellows
Coupling
3.20"
NW-25 Flange with EVAC chain clamp
0.45"
0.50"
2.00"
0.75"
0.49"
35.97"
30.67"
1.83"
29.77"
Las er Beam
0.75"
1.50"
ø 2.75"
3.00"
6.00"
0.10"
0.10"
1.83"
Brewster Angle Window
1.75"
Mount constructed in-house
4.00 " long chamber with two
2 3/4" CF flanges centrally located
at 90 degrees to each other.
Vacuum Envelope
Chamber for Sample Gas
Chamber Containing Helium Gas
Cyrogenic Chamber
1/4" OD tubing with Cajon VCR male gland attached.
These are positioned on each side of central chamber;
only location of attachment to 0.75" tube shown here
for clarity. They also have 90 degree bends as shown
for the fittings on the 1.5" dia. helium gas chamber
which surrounds the 0.75" dia. sample gas chamber.
3 3/8 " CF Flange
0.75"
0.50"
0.50"
NW-16 flange with
EVAC chain clamp
End view showing
Cajon VCR glands
3" diameter
Inner Cell
2 3/4 "
CF Flange
90.0°
2 3/4 "
CF Flange
0.30"
0.30"
End view of vacuum envelope chamber showing end view of Inner Cell,
NW flange with chain clamp, and ends of 4 VCR male glands, 2 of which are
attached to helium gas chamber (at 6 and 12 o'clock positions) and 2 of which
are attached to sample gas chamber (at 9 and 3 o'clock positions). End flanges
for vacuum envelope are ISO-160 Optional Fastener Flanges. There are 10
ports attached to the vacuum envelope chamber, 5 ports on each end.
NW-40 Flange
NW-40 Flange
End view of main chamber showing port attachments to
main chamber, end view of Inner Cell, ends of four VCR
fittings which are attached to 1/4" tubing. Two of the latter
are attached to the helium gas chamber, and two are
attached to the sample chamber.
Design of the four walled cryogenic chamber
Performance of the chamber for -112 °C
Performance of the chamber for -142 °C
Effective Temperature is -142 oC
T1 - at center of the cell
T2 - at end of the cell
Pressure
100
90
80
50
0
60
50
-50
40
-100
30
20
-150
10
-200
0
0
15
30
45
60
75
Time (minutes)
90
105
120
135
Pressure (torr)
Temperature (oC)
70
Performance of the chamber for -174 °C
o
Effective temperature is -174 C
T1 - at center of the cell
T2 - at end of the cell
Pressure
90
80
80
70
60
-20
50
-70
40
-120
30
20
-170
-220 0
10
20
40
60
80
Time (minutes)
100
120
1400
Pressure (torr)
o
Temperature ( C)
30
Temperature calculated using gas laws
Type of
Gas
Set Temp.
(oC)
Initial Pressure
(torr)
Final Pressure
(torr)
Calculated
Temp. (oC)
Oxygen
-150
4.115
1.990
-130.95
Oxygen
-150
50.583
24.160
-133.037
Oxygen
-150
80.260
37.726
-133.946
Oxygen
-150
82.117
39.520
-130.575
Oxygen
-150
80.090
38.212
-131.66
Oxygen
-150
80.970
38.880
-132.58
Helium
-150
5.500
2.673
-130.58
Helium
-150
52.963
25.120
-133.92
Argon
-150
5.592
2.712
-130.687
Argon
-150
52.885
25.692
-130.2
Methane
-150
5.129
2.464
-132.127
Methane
-150
51.035
25.145
-128.32
Oxygen
-165
4.061
1.839
-140.94
Oxygen
-165
51.390
22.991
-142.18
Oxygen
-165
80.809
36.190
-141.42
Oxygen
-165
80.590
36.084
-141.4
Oxygen
-165
80.324
35.932
-141.29
Helium
-165
5.534
2.412
-145.94
Helium
-165
58.353
26.591
-140.173
Argon
-165
5.538
2.484
-141.3
Argon
-165
54.291
24.340
-141.77
Temperature calculated using gas laws
Type of Gas
Set Temp.
(oC)
Initial Pressure
(torr)
Final Pressure
(torr)
Calculated
Temp. (oC)
Methane
-165
5.140
2.294
-141.89
Methane
-165
51.431
23.170
-141.89
Oxygen
-196
5.574
1.878
-174.045
Oxygen
-196
52.407
17.903
-172.596
Oxygen
-196
79.815
27.322
-173.416
Oxygen
-196
79.840
27.265
-173.04
Oxygen
-196
80.735
26.938
-174.4
Helium
-196
5.672
1.866
-176.445
Helium
-196
50.537
16.904
-174.76
Argon
-196
5.364
1.802
-174.57
Argon
-196
51.801
17.444
-174.33
Methane
-196
5.181
1.742
-174.28
Methane
-196
6.105
2.071
-173.34
Methane
-196
21.274
7.033
-175.44
Methane
-196
50.166
9.471
Methane
-196
80.525
9.731
A section of the intracavity laser spectrum of oxygen A band
at -174 °C showing the original and deconvolved data
296 K
Temperature checks – literature values
L R Brown and C Plymate, J. Molecular Spectroscopy 199, 166-179 (2000)
296 K
Temperature checks – literature values
Roland Schermaul and Richard C.M.Learner, J. Quant. Spectrosc. Radiat. Transfer, 61 (6) 781-794 (1999)
198 K
Temperature checks – literature values
Roland Schermaul and Richard C.M.Learner, J. Quant. Spectrosc. Radiat. Transfer, 61 (6) 781-794 (1999)
Our experimental data
-112 °C
Our experimental data
-142 °C
Our experimental data
-174 °C
A section of intracavity laser spectrum of methane for three temperatures
The spectrum is normalized to methane pressure 2 torr and pathlength 5 km
A section of the methane spectrum in 889 nm band showing the original
and deconvolved data. The spectrum is normalized to methane pressure 2
torr and pathlength 5 km.
Methane absorption coefficients for the 889 nm band derived
from ILS spectra for three temperatures averaged per Å
Conclusions
A four-walled cryogenic chamber that can be used for low
temperature ILS studies is described
760 nm Oxygen A band is used to determine the rotational
temperature.
The effective temperature in the chamber is in good agreement
with that calculated from the gas laws.
Methane spectra is recorded for 889 nm band at different low
sample temperatures.
Absorption coefficients for the 889 nm band at three low
temperatures are determined.
Acknowledgements
Support from NASA’s Planetary Atmospheres Program (NAG5-12013) is
gratefully acknowledged.
Additional supplemental funding from National Science Foundation (CHE0213356) and University of Missouri Research Board for the Verdi laser is
gratefully acknowledged.
Thanks to Norman (Ted) Windsor, UMSl Chemistry Machinist for fabricating
the Brewster angle window mounts.
Thank you
Thermal transpiration check
Set
Temperature
(°C)
Initial
Pressure
(torr)
Final
Pressure
(torr)
Pressure
change
(torr)
Temperature
calculated
(°C)
Gauge 1
-196
62.758
24.252
38.506a
-159.286
Gauge 2
-196
62.89
24.29
38.6
-159.347
Gauge 1
-196
62.099
22.84
39.259b
-164.37
Gauge 2
-196
62.26
22.86
39.4
-164.559
Gauge 1
-165
60.592
28.526
32.066c
-134.573
Gauge 2
-165
60.72
28.56
32.16
-134.701
a
after 2 hours and 30 minutes
after 4 hours and 30 minutes
c after 4 hours and 30 minutes
for Helium as sample gas
Leak rate is 10-4 torr/minute while the chamber envelope is under vacuum and 1.5 * 10 -3 torr/minute while envelope
is at atmospheric pressure
b
Absorption coefficients (km-1 am-1) per Ao for 889 nm band of methane at -112 oC
derived from intracavity laser spectroscopy measurements.
8691.9
8692.5
8693.5
8694.5
8695.5
8696.5
8697.5
8698.5
8699.5
8700.5
8701.5
8702.5
8703.5
8704.5
8705.5
8706.5
8707.5
8708.5
8709.5
8710.5
8711.5
8712.5
8713.5
8714.5
8715.5
8716.5
8717.5
8718.5
8719.5
8720.5
8721.5
8722.5
8723.5
8724.5
8725.5
8726.5
8727.5
8728.5
8729.5
8730.5
8731.5
8732.5
8733.5
8734.5
8735.5
0.45
3.49
3.91
3.02
3.30
2.67
3.79
4.27
4.37
3.19
3.31
3.32
3.41
4.57
2.90
3.11
3.08
2.67
2.69
2.45
2.93
2.50
2.33
2.74
2.48
1.85
1.76
2.09
2.64
1.89
1.69
2.01
2.19
2.01
2.21
2.32
2.18
1.30
1.89
2.46
1.46
1.31
1.41
1.27
1.71
8736.5
8737.5
8738.5
8739.5
8740.5
8741.5
8742.5
8743.5
8744.5
8745.5
8746.5
8747.5
8748.5
8749.5
8750.5
8751.5
8752.5
8753.5
8754.5
8755.5
8756.5
8757.5
8758.5
8759.5
8760.5
8761.5
8762.5
8763.5
8764.5
8765.5
8766.5
8767.5
8768.5
8769.5
8770.5
8771.5
8772.5
8773.5
8774.5
8775.5
8776.5
8777.5
8778.5
8779.5
8780.5
1.70
1.71
1.53
1.45
1.30
1.97
1.86
1.60
1.68
1.68
2.05
1.55
1.69
1.33
1.85
1.26
1.58
1.84
1.58
1.90
1.76
1.91
1.97
1.91
2.06
1.89
1.99
1.76
2.11
2.07
1.88
1.79
2.66
2.07
1.83
1.89
1.71
2.54
2.49
1.83
2.25
2.00
1.64
2.47
2.61
8781.5
8782.5
8783.5
8784.5
8785.5
8786.5
8787.5
8788.5
8789.5
8790.5
8791.5
8792.5
8793.5
8794.5
8795.5
8796.5
8797.5
8798.5
8799.5
8800.5
8801.5
8802.5
8803.5
8804.5
8805.5
8806.5
8807.5
8808.5
8809.5
8810.5
8811.5
8812.5
8813.5
8814.5
8815.5
8816.5
8817.5
8818.5
8819.5
8820.5
8821.5
8822.5
8823.5
8824.5
8825.5
2.48
2.48
2.54
1.84
2.52
2.92
2.89
3.11
2.78
3.35
4.29
3.81
4.81
4.65
4.57
5.66
6.85
10.52
10.08
8.34
10.71
8.85
9.18
9.73
8.67
12.92
10.63
13.28
13.20
14.24
19.30
24.05
21.44
25.59
21.30
24.87
27.56
30.94
30.81
28.98
19.02
35.82
29.06
25.29
36.12
8826.5
8827.5
8828.5
8829.5
8830.5
8831.5
8832.5
8833.5
8834.5
8835.5
8836.5
8837.5
8838.5
8839.5
8840.5
8841.5
8842.5
8843.5
8844.5
8845.5
8846.5
8847.5
8848.5
8849.5
8850.5
8851.5
8852.5
8853.5
8854.5
8855.5
8856.5
8857.5
8858.5
8859.5
8860.5
8861.5
8862.5
8863.5
8864.5
8865.5
8866.5
8867.5
8868.5
8869.5
8870.5
23.01
29.28
36.61
27.63
40.86
59.15
62.58
38.29
41.69
39.54
76.94
53.25
31.87
32.65
24.88
28.36
36.47
55.50
33.51
29.17
18.85
16.15
20.22
21.38
30.61
16.76
22.47
24.43
57.09
18.66
20.68
16.51
31.56
84.89
21.12
24.93
19.30
35.96
40.37
33.92
64.46
72.18
113.4
59.29
50.48
8871.5
8872.5
8873.5
8874.5
8875.5
8876.5
8877.5
8878.5
8879.5
8880.5
8881.5
8882.5
8883.5
8884.5
8885.5
8886.5
8887.5
8888.5
8889.5
8890.5
8891.5
8892.5
8893.5
8894.5
8895.5
8896.5
8897.5
8898.5
8899.5
8900.5
8901.5
8902.5
8903.5
8904.5
8905.5
8906.5
8907.5
8908.5
8909.5
8910.5
8911.5
8912.5
8913.5
8914.5
8915.5
48.65
50.90
70.21
55.46
45.08
33.45
49.33
28.55
32.19
30.36
30.16
45.50
44.28
22.29
19.72
19.76
30.43
25.39
18.35
24.69
29.77
74.58
28.47
26.53
14.61
20.68
19.15
28.34
28.50
29.16
61.36
33.61
31.53
38.03
26.64
21.77
18.91
22.17
35.24
27.79
28.73
38.78
31.54
18.72
21.13
8916.5
8917.5
8918.5
8919.5
8920.5
8921.5
8922.5
8923.5
8924.5
8925.5
8926.5
8927.5
8928.5
8929.5
8930.5
8931.5
8932.5
8933.5
8934.5
8935.5
8936.5
8937.5
8938.5
8939.5
8940.5
8941.5
8942.5
8943.5
8944.5
8945.5
8946.5
8947.5
8948.5
8949.5
8950.5
8951.5
8952.5
8953.5
8954.5
8955.5
8956.5
8957.5
8958.5
8959.5
8960.5
8961.5
8962.5
8963.5
8964.5
23.46
17.76
24.26
19.66
22.02
29.21
20.62
23.02
24.08
28.28
27.63
16.91
18.23
18.91
17.94
18.73
16.99
23.63
26.88
35.79
21.30
25.82
24.92
31.02
23.26
19.53
20.51
20.86
35.88
17.51
26.16
24.80
23.93
21.44
24.71
21.82
17.09
20.73
29.69
23.44
32.74
23.34
28.72
24.19
21.66
21.55
18.69
29.37
17.03
8965.5
8966.5
8967.5
8968.5
8969.5
8970.5
8971.5
8972.5
8973.5
8974.5
8975.5
8976.5
8977.5
8978.5
8979.5
8980.5
8981.5
8982.5
8983.5
8984.5
8985.5
8986.5
8987.5
8988.5
8989.5
8990.5
8991.5
8992.5
8993.5
8994.5
8995.5
8996.5
8997.5
8998.5
8999.5
9000.5
9001.5
9002.5
9003.5
9004.5
9005.5
9006.5
9007.5
9008.5
9009.5
9010.5
9011.5
9012.5
9013.5
17.67
18.98
21.10
19.16
16.91
14.74
13.09
23.20
19.68
12.16
17.38
14.30
16.99
13.98
16.68
22.54
11.97
14.02
17.83
17.73
21.33
26.70
21.50
27.63
13.87
24.64
26.49
17.44
14.17
19.11
11.55
17.42
13.92
14.93
13.85
15.35
17.40
9.63
10.36
14.69
16.30
12.39
13.01
15.06
13.52
20.71
17.65
10.31
13.53
9014.5
9015.5
9016.5
9017.5
9018.5
9019.5
9020.5
9021.5
9022.5
9023.5
9024.5
9025.5
9026.5
9027.5
9028.5
9029.5
9030.5
9031.5
9032.5
9033.5
9034.5
9035.5
9036.5
9037.5
9038.5
9039.5
9040.5
9041.5
9042.5
9043.5
9044.5
9045.5
9046.5
9047.5
9048.5
9049.5
9050.5
9051.5
9052.5
9053.5
9054.5
9055.5
9056.5
9057.5
9058.5
9059.5
9060.5
9061.5
9062.5
6.41
12.55
6.03
13.11
11.00
6.39
8.56
8.22
12.33
7.66
8.62
8.22
5.67
11.73
9.88
7.16
5.74
4.83
6.80
7.50
7.90
5.67
4.73
4.25
3.92
4.16
4.77
3.77
5.55
5.08
5.57
5.04
4.05
3.75
4.47
4.00
3.33
3.49
3.40
3.35
3.28
2.87
3.20
3.31
3.18
2.50
3.18
2.50
2.50
9063.5
9064.5
9065.5
9066.5
9067.5
9068.5
9069.5
9070.5
9071.5
9072.5
9073.5
9074.5
9075.5
9076.5
9077.5
9078.5
9079.5
9080.5
9081.5
9082.5
9083.5
9084.5
9085.5
9086.5
9087.5
9088.5
9089.5
9090.5
9091.5
9092.5
9093.5
9094.5
9095.5
9096.5
9097.5
9098.5
9099.5
9100.5
9101.5
9102.5
9103.5
9104.5
9105.5
9106.5
9107.5
9108.5
9109.5
9110.5
9111.5
3.29
3.65
2.36
1.88
1.76
2.76
2.44
2.92
3.32
2.12
1.94
1.40
2.38
1.67
1.74
1.35
1.81
1.81
2.20
2.19
1.53
1.50
1.73
3.40
2.46
1.86
1.70
1.12
1.10
0.88
0.78
1.03
1.13
1.34
0.94
1.67
2.02
1.48
0.77
0.75
1.23
1.08
1.21
1.04
1.27
1.27
1.85
1.22
1.74
9112.5
9113.5
9114.5
9115.5
9116.5
9117.5
9118.5
9119.5
9120.5
9121.5
9122.5
9123.5
9124.5
9125.5
9126.5
9127.5
9128.5
9129.5
9130.5
9131.5
9132.5
9133.5
9134.5
9135.5
9136.5
9137.5
9138.5
9139.5
9140.5
9141.5
9142.5
9143.5
9144.5
9145.5
9146.5
9147.5
9148.5
9149.5
9150.5
9151.5
9152.1
1.11
1.80
0.77
1.48
1.10
1.58
1.73
1.34
0.78
1.22
1.37
0.84
1.38
1.41
1.42
1.46
1.95
2.19
1.93
1.66
1.42
0.96
0.95
1.26
1.11
1.04
0.64
1.33
1.08
0.90
1.49
0.69
1.02
1.05
0.78
1.08
0.85
1.47
1.26
0.81
0.12
Absorption coefficients (km-1 am-1) per A o for 889 nm band of methane at -142 oC
derived from intracavity laser spectroscopy measurements
8691.9
8692.5
8693.5
8694.5
8695.5
8696.5
8697.5
8698.5
8699.5
8700.5
8701.5
8702.5
8703.5
8704.5
8705.5
8706.5
8707.5
8708.5
8709.5
8710.5
8711.5
8712.5
8713.5
8714.5
8715.5
8716.5
8717.5
8718.5
8719.5
8720.5
8721.5
8722.5
8723.5
8724.5
8725.5
8726.5
8727.5
8728.5
8729.5
8730.5
8731.5
8732.5
8733.5
8734.5
8735.5
8736.5
0.48
3.28
3.10
2.20
2.65
2.18
2.59
3.13
3.19
2.19
2.28
2.33
2.47
3.57
2.39
2.10
2.20
1.96
1.97
1.63
2.37
2.12
1.77
1.98
1.88
1.51
1.56
1.73
1.97
1.47
1.29
1.67
1.80
1.37
1.67
1.87
1.86
1.18
1.45
1.78
1.01
1.09
1.16
1.13
1.54
1.48
8737.5
8738.5
8739.5
8740.5
8741.5
8742.5
8743.5
8744.5
8745.5
8746.5
8747.5
8748.5
8749.5
8750.5
8751.5
8752.5
8753.5
8754.5
8755.5
8756.5
8757.5
8758.5
8759.5
8760.5
8761.5
8762.5
8763.5
8764.5
8765.5
8766.5
8767.5
8768.5
8769.5
8770.5
8771.5
8772.5
8773.5
8774.5
8775.5
8776.5
8777.5
8778.5
8779.5
8780.5
8781.5
8782.5
1.55
1.29
1.34
1.35
1.71
1.61
1.36
1.39
1.25
1.51
1.12
1.11
0.87
1.40
0.84
1.19
1.47
1.35
1.56
1.31
1.42
1.46
1.40
1.70
1.38
1.44
1.32
1.57
1.57
1.45
1.30
1.90
1.45
1.39
1.42
1.27
1.91
1.96
1.40
1.73
1.54
1.47
2.08
2.22
1.94
2.00
8783.5
8784.5
8785.5
8786.5
8787.5
8788.5
8789.5
8790.5
8791.5
8792.5
8793.5
8794.5
8795.5
8796.5
8797.5
8798.5
8799.5
8800.5
8801.5
8802.5
8803.5
8804.5
8805.5
8806.5
8807.5
8808.5
8809.5
8810.5
8811.5
8812.5
8813.5
8814.5
8815.5
8816.5
8817.5
8818.5
8819.5
8820.5
8821.5
8822.5
8823.5
8824.5
8825.5
8826.5
8827.5
8828.5
2.08
1.48
1.92
2.25
2.28
2.36
2.02
2.37
2.48
2.41
3.29
3.28
2.99
3.80
4.39
7.72
6.84
5.97
7.46
6.25
6.96
7.22
6.55
9.33
6.65
8.64
8.30
7.63
12.78
16.07
15.22
20.57
19.29
22.82
27.45
26.08
27.40
27.99
18.87
30.50
27.27
25.32
39.44
24.51
31.19
36.88
8829.5
8830.5
8831.5
8832.5
8833.5
8834.5
8835.5
8836.5
8837.5
8838.5
8839.5
8840.5
8841.5
8842.5
8843.5
8844.5
8845.5
8846.5
8847.5
8848.5
8849.5
8850.5
8851.5
8852.5
8853.5
8854.5
8855.5
8856.5
8857.5
8858.5
8859.5
8860.5
8861.5
8862.5
8863.5
8864.5
8865.5
8866.5
8867.5
8868.5
8869.5
8870.5
8871.5
8872.5
8873.5
8874.5
28.34
40.43
57.45
65.94
44.22
53.18
53.99
92.80
55.95
42.00
41.84
29.40
31.79
39.49
60.45
36.95
25.99
15.77
15.46
22.48
23.37
34.86
19.90
29.29
34.69
60.66
26.03
25.46
25.07
46.21
124.9
38.45
30.82
22.97
37.03
65.15
51.13
86.87
99.77
128.7
81.65
68.64
54.68
56.47
73.74
60.16
8875.5
8876.5
8877.5
8878.5
8879.5
8880.5
8881.5
8882.5
8883.5
8884.5
8885.5
8886.5
8887.5
8888.5
8889.5
8890.5
8891.5
8892.5
8893.5
8894.5
8895.5
8896.5
8897.5
8898.5
8899.5
8900.5
8901.5
8902.5
8903.5
8904.5
8905.5
8906.5
8907.5
8908.5
8909.5
8910.5
8911.5
8912.5
8913.5
8914.5
8915.5
8916.5
8917.5
8918.5
8919.5
8920.5
41.30
31.07
52.04
28.51
33.93
36.29
31.18
42.77
49.29
25.73
24.37
21.65
34.02
25.36
19.28
28.00
37.90
109.5
41.66
31.32
15.24
24.17
23.26
34.32
37.63
35.78
73.57
38.21
37.17
45.01
27.96
25.21
22.54
24.25
37.77
26.89
31.35
46.45
34.90
23.98
23.81
24.22
19.74
28.16
19.40
23.34
8921.5
8922.5
8923.5
8924.5
8925.5
8926.5
8927.5
8928.5
8929.5
8930.5
8931.5
8932.5
8933.5
8934.5
8935.5
8936.5
8937.5
8938.5
8939.5
8940.5
8941.5
8942.5
8943.5
8944.5
8945.5
8946.5
8947.5
8948.5
8949.5
8950.5
8951.5
8952.5
8953.5
8954.5
8955.5
8956.5
8957.5
8958.5
8959.5
8960.5
8961.5
8962.5
8963.5
8964.5
8965.5
8966.5
8967.5
28.38
24.23
23.68
25.98
31.27
37.06
23.08
21.08
22.81
21.43
20.68
18.79
26.41
27.43
35.24
22.01
29.21
27.12
32.58
25.50
28.99
24.37
21.93
40.35
18.18
27.51
27.25
26.21
23.52
26.76
24.31
19.44
23.40
33.83
29.61
40.21
32.25
39.00
28.25
25.87
31.90
35.95
34.66
16.24
19.12
19.49
19.02
8968.5
8969.5
8970.5
8971.5
8972.5
8973.5
8974.5
8975.5
8976.5
8977.5
8978.5
8979.5
8980.5
8981.5
8982.5
8983.5
8984.5
8985.5
8986.5
8987.5
8988.5
8989.5
8990.5
8991.5
8992.5
8993.5
8994.5
8995.5
8996.5
8997.5
8998.5
8999.5
9000.5
9001.5
9002.5
9003.5
9004.5
9005.5
9006.5
9007.5
9008.5
9009.5
9010.5
9011.5
9012.5
9013.5
9014.5
9015.5
18.81
17.46
15.97
24.71
34.25
25.69
15.96
22.47
15.60
20.56
17.39
22.20
31.00
19.28
18.67
24.32
24.27
24.96
37.53
40.96
46.18
19.56
33.99
40.82
32.22
22.55
20.66
12.01
18.05
15.06
15.41
13.07
16.35
18.15
9.65
11.69
13.74
14.17
10.66
12.27
15.65
13.59
21.53
18.30
10.95
14.59
6.79
17.66
9016.5
9017.5
9018.5
9019.5
9020.5
9021.5
9022.5
9023.5
9024.5
9025.5
9026.5
9027.5
9028.5
9029.5
9030.5
9031.5
9032.5
9033.5
9034.5
9035.5
9036.5
9037.5
9038.5
9039.5
9040.5
9041.5
9042.5
9043.5
9044.5
9045.5
9046.5
9047.5
9048.5
9049.5
9050.5
9051.5
9052.5
9053.5
9054.5
9055.5
9056.5
9057.5
9058.5
9059.5
9060.5
9061.5
9062.5
9063.5
15.43
18.75
12.35
6.46
8.52
7.16
13.16
7.93
11.04
10.93
8.66
12.13
9.19
6.36
4.88
4.54
6.32
7.04
6.75
5.17
4.49
3.87
3.45
3.97
4.93
4.07
6.32
5.23
5.71
5.09
4.06
4.03
4.95
4.57
3.24
3.41
2.77
3.81
3.67
2.90
2.83
3.62
3.56
2.71
2.87
2.18
2.56
3.15
9064.5
9065.5
9066.5
9067.5
9068.5
9069.5
9070.5
9071.5
9072.5
9073.5
9074.5
9075.5
9076.5
9077.5
9078.5
9079.5
9080.5
9081.5
9082.5
9083.5
9084.5
9085.5
9086.5
9087.5
9088.5
9089.5
9090.5
9091.5
9092.5
9093.5
9094.5
9095.5
9096.5
9097.5
9098.5
9099.5
9100.5
9101.5
9102.5
9103.5
9104.5
9105.5
9106.5
9107.5
9108.5
9109.5
9110.5
9111.5
3.04
2.06
1.49
1.47
1.94
1.96
2.78
3.08
1.97
2.05
0.97
2.26
1.68
1.91
1.50
2.98
2.66
3.09
2.30
1.83
2.68
3.39
4.06
1.25
0.95
1.19
1.03
1.10
0.76
0.70
0.91
0.91
1.18
0.95
1.44
1.50
1.46
0.77
0.74
1.34
1.04
0.99
0.92
1.23
1.12
1.68
1.07
1.71
9112.5
9113.5
9114.5
9115.5
9116.5
9117.5
9118.5
9119.5
9120.5
9121.5
9122.5
9123.5
9124.5
9125.5
9126.5
9127.5
9128.5
9129.5
9130.5
9131.5
9132.5
9133.5
9134.5
9135.5
9136.5
9137.5
9138.5
9139.5
9140.5
9141.5
9142.5
9143.5
9144.5
9145.5
9146.5
9147.5
9148.5
9149.5
9150.5
9151.5
9152.5
9153.5
9154.5
9155.3
1.11
2.03
0.80
1.59
0.89
1.59
1.57
1.40
0.90
1.16
1.43
0.96
1.63
1.84
1.51
1.12
1.61
1.62
1.81
2.05
1.68
1.10
1.08
1.38
0.93
0.88
0.87
1.46
1.20
1.25
2.15
1.12
1.31
1.05
0.84
1.11
1.13
1.85
1.49
0.96
1.28
1.22
0.74
0.54
Absorption coefficients (km-1 am -1) per Ao for 889 nm band of methane at -174 oC
derived from intracavity laser spectroscopy measurements.
8691.9
8692.5
8693.5
8694.5
8695.5
8696.5
8697.5
8698.5
8699.5
8700.5
8701.5
8702.5
8703.5
8704.5
8705.5
8706.5
8707.5
8708.5
8709.5
8710.5
8711.5
8712.5
8713.5
8714.5
8715.5
8716.5
8717.5
8718.5
8719.5
8720.5
8721.5
8722.5
8723.5
8724.5
8725.5
8726.5
8727.5
8728.5
8729.5
8730.5
8731.5
8732.5
8733.5
8734.5
8735.5
8736.5
8737.5
8738.5
8739.5
0.01
4.11
4.17
3.38
3.80
2.89
3.36
4.01
4.07
2.63
2.82
3.35
3.30
4.37
2.88
2.51
2.42
2.28
2.53
2.15
3.12
2.59
1.82
2.67
2.24
1.68
1.54
2.05
2.42
1.92
1.53
2.01
2.25
1.85
2.00
2.32
2.20
1.33
1.61
2.03
1.19
1.03
1.24
1.34
1.84
2.01
2.04
1.63
1.86
8740.5
8741.5
8742.5
8743.5
8744.5
8745.5
8746.5
8747.5
8748.5
8749.5
8750.5
8751.5
8752.5
8753.5
8754.5
8755.5
8756.5
8757.5
8758.5
8759.5
8760.5
8761.5
8762.5
8763.5
8764.5
8765.5
8766.5
8767.5
8768.5
8769.5
8770.5
8771.5
8772.5
8773.5
8774.5
8775.5
8776.5
8777.5
8778.5
8779.5
8780.5
8781.5
8782.5
8783.5
8784.5
8785.5
8786.5
8787.5
8788.5
1.62
2.55
2.49
1.74
1.75
1.70
2.02
1.42
1.30
1.07
1.76
1.04
1.52
1.98
1.65
1.76
1.61
2.00
2.00
1.82
2.08
1.73
1.97
1.77
2.16
2.22
1.75
1.80
2.50
2.17
1.86
1.77
1.58
2.35
2.52
2.13
2.67
2.15
1.86
2.62
2.82
2.42
2.34
2.43
1.91
2.37
2.74
2.67
2.68
8789.5
8790.5
8791.5
8792.5
8793.5
8794.5
8795.5
8796.5
8797.5
8798.5
8799.5
8800.5
8801.5
8802.5
8803.5
8804.5
8805.5
8806.5
8807.5
8808.5
8809.5
8810.5
8811.5
8812.5
8813.5
8814.5
8815.5
8816.5
8817.5
8818.5
8819.5
8820.5
8821.5
8822.5
8823.5
8824.5
8825.5
8826.5
8827.5
8828.5
8829.5
8830.5
8831.5
8832.5
8833.5
8834.5
8835.5
8836.5
8837.5
2.44
2.70
3.17
2.78
3.30
3.22
3.24
4.30
4.31
6.00
6.22
6.16
7.57
6.54
7.73
8.18
7.23
11.05
6.99
9.27
7.19
5.94
9.57
11.67
13.22
15.22
17.36
20.68
22.80
22.67
25.10
26.42
16.98
26.69
23.79
21.44
38.70
26.59
32.01
35.16
30.15
45.50
66.63
83.30
46.82
47.74
44.29
80.08
77.65
8838.5
8839.5
8840.5
8841.5
8842.5
8843.5
8844.5
8845.5
8846.5
8847.5
8848.5
8849.5
8850.5
8851.5
8852.5
8853.5
8854.5
8855.5
8856.5
8857.5
8858.5
8859.5
8860.5
8861.5
8862.5
8863.5
8864.5
8865.5
8866.5
8867.5
8868.5
8869.5
8870.5
8871.5
8872.5
8873.5
8874.5
8875.5
8876.5
8877.5
8878.5
8879.5
8880.5
8881.5
8882.5
8883.5
8884.5
8885.5
8886.5
52.51
51.37
37.77
50.95
60.60
91.31
57.36
47.01
26.60
23.66
32.97
46.46
68.22
39.77
43.05
38.40
67.25
27.71
39.30
35.96
57.60
165.6
56.32
32.11
30.73
54.53
66.91
46.49
99.55
114.8
117.1
79.67
60.06
54.32
68.97
72.54
62.53
40.73
33.51
54.58
34.93
37.86
33.30
32.94
60.54
73.86
29.25
22.45
25.50
8887.5
8888.5
8889.5
8890.5
8891.5
8892.5
8893.5
8894.5
8895.5
8896.5
8897.5
8898.5
8899.5
8900.5
8901.5
8902.5
8903.5
8904.5
8905.5
8906.5
8907.5
8908.5
8909.5
8910.5
8911.5
8912.5
8913.5
8914.5
8915.5
8916.5
8917.5
8918.5
8919.5
8920.5
8921.5
8922.5
8923.5
8924.5
8925.5
8926.5
8927.5
8928.5
8929.5
8930.5
8931.5
8932.5
8933.5
8934.5
8935.5
36.38
24.55
21.50
27.45
39.80
99.76
43.66
36.02
17.62
29.66
29.14
40.70
29.50
29.60
65.04
38.57
37.13
48.45
35.95
34.25
28.04
26.75
44.96
33.03
33.28
48.08
35.15
18.92
23.34
25.64
21.91
36.59
20.16
27.30
27.67
24.22
20.42
28.18
45.22
23.40
19.49
17.88
25.15
23.54
21.78
19.84
28.13
30.06
35.65
8936.5
8937.5
8938.5
8939.5
8940.5
8941.5
8942.5
8943.5
8944.5
8945.5
8946.5
8947.5
8948.5
8949.5
8950.5
8951.5
8952.5
8953.5
8954.5
8955.5
8956.5
8957.5
8958.5
8959.5
8960.5
8961.5
8962.5
8963.5
8964.5
8965.5
8966.5
8967.5
8968.5
8969.5
8970.5
8971.5
8972.5
8973.5
8974.5
8975.5
8976.5
8977.5
8978.5
8979.5
26.78
32.13
31.10
40.35
28.62
23.59
22.44
20.37
43.97
17.46
27.66
29.68
27.82
22.12
26.17
23.16
17.72
23.19
35.03
31.26
42.01
31.57
43.34
31.32
28.76
38.94
26.70
48.45
20.74
20.69
23.76
23.46
33.96
19.36
18.30
11.73
37.71
30.18
28.13
28.59
23.74
27.76
19.04
25.55
8980.5
8981.5
8982.5
8983.5
8984.5
8985.5
8986.5
8987.5
8988.5
8989.5
8990.5
8991.5
8992.5
8993.5
8994.5
8995.5
8996.5
8997.5
8998.5
8999.5
9000.5
9001.5
9002.5
9003.5
9004.5
9005.5
9006.5
9007.5
9008.5
9009.5
9010.5
9011.5
9012.5
9013.5
9014.5
9015.5
9016.5
9017.5
9018.5
9019.5
9020.5
9021.5
9022.5
9023.5
35.38
20.09
21.53
28.87
33.07
29.44
34.33
27.35
40.75
13.28
23.29
24.72
21.95
17.92
24.12
17.50
22.90
19.20
17.31
15.11
15.22
19.51
8.56
11.88
15.98
14.78
10.96
12.73
16.91
14.71
24.00
17.01
10.44
17.88
9.60
18.24
11.27
23.10
17.92
7.63
8.42
8.17
14.95
9.12
9024.5
9025.5
9026.5
9027.5
9028.5
9029.5
9030.5
9031.5
9032.5
9033.5
9034.5
9035.5
9036.5
9037.5
9038.5
9039.5
9040.5
9041.5
9042.5
9043.5
9044.5
9045.5
9046.5
9047.5
9048.5
9049.5
9050.5
9051.5
9052.5
9053.5
9054.5
9055.5
9056.5
9057.5
9058.5
9059.5
9060.5
9061.5
9062.5
9063.5
9064.5
9065.5
9066.5
9067.5
12.16
9.94
4.91
12.61
10.91
7.69
6.22
4.60
6.60
8.33
6.29
4.96
5.27
4.20
2.86
3.76
4.40
4.22
6.26
4.60
4.81
3.89
3.24
3.92
4.96
4.49
2.96
3.02
2.34
3.20
3.53
2.96
2.62
3.31
2.84
2.32
2.84
1.99
2.62
2.78
2.68
2.35
1.71
1.70
9068.5
9069.5
9070.5
9071.5
9072.5
9073.5
9074.5
9075.5
9076.5
9077.5
9078.5
9079.5
9080.5
9081.5
9082.5
9083.5
9084.5
9085.5
9086.5
9087.5
9088.5
9089.5
9090.5
9091.5
9092.5
9093.5
9094.5
9095.5
9096.5
9097.5
9098.5
9099.5
9100.5
9101.5
9102.5
9103.5
9104.5
9105.5
9106.5
9107.5
9108.5
9109.5
9110.5
9111.5
2.99
2.92
3.27
3.31
3.95
3.50
1.99
2.51
1.50
1.76
1.41
3.03
2.35
2.77
2.25
1.19
1.50
1.48
3.17
1.97
1.06
1.38
1.16
1.36
0.98
0.82
1.26
1.26
1.25
0.95
1.23
1.34
1.18
0.75
0.71
1.52
1.14
1.17
1.15
1.46
1.31
1.94
1.10
1.93
9112.5
9113.5
9114.5
9115.5
9116.5
9117.5
9118.5
9119.5
9120.5
9121.5
9122.5
9123.5
9124.5
9125.5
9126.5
9127.5
9128.5
9129.5
9130.5
9131.5
9132.5
9133.5
9134.5
9135.5
9136.5
9137.5
9138.5
9139.5
9140.5
9141.5
9142.5
9143.5
9144.5
9145.5
9146.5
9147.5
9148.5
9149.5
9150.5
9151.5
9152.5
9153.5
9154.5
9155.3
1.31
2.83
1.10
2.52
1.26
2.31
2.25
2.49
1.75
1.64
1.54
1.07
2.34
2.65
1.94
1.59
2.66
3.03
3.47
3.95
2.97
1.62
1.48
2.03
1.41
1.18
1.24
2.47
2.07
1.34
2.97
1.37
1.92
1.91
1.67
1.83
1.53
2.98
2.19
1.31
3.09
3.45
2.98
1.72