Linda R. Brown and Robert A. Toth, "Comparison of the frequencies of NH3, CO2, H2O, N2O, CO, and CH4 as infrared calibration standards," J. Opt. Soc. Am. B 2, 842-856 (1985)
The absolute accuracies of infrared calibration standards for line positions have been investigated using a 0.0056-cm−1-resolution (unapodized) Fourier-transform spectrum recorded from 550 to 5000 cm−1. The spectrum has been obtained using a multicell arrangement containing the various molecular species. Detailed comparisons reveal that standards for CO2, CH4, and N2O obtained from laser research and NH3 from Fourier-transform spectrometer research are consistent within the accuracies of the present data (±0.0001 cm−1). However, certain N2O, H2O, and CO values in the 1100- to 2300-cm−1 region are systematically high by 0.0001 to 0.0004 cm−1. Correction factors for the H2O and CO standards are obtained to bring these into agreement with the laser values. In addition, corrected values for the 2ν2 and ν1 bands of N2O at 9 μm are reported.
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The line positions are in units of inverse centimeters. The literature values for NH3, CO2, N2O (at 9 μm), H2O, CO, CH4, and N2O (at 2.2 μm) have been taken from Refs. 15, 2, 11, 10, 8, 1, and 5, respectively. The rotational assignment consists of the upper state and lower state: J′, K′, J″, K″ for NH3; △J, J″ for CO2, CO, and N2O: J′, Ka′, Kc′, J″, Ka″, Kc″ for H2O; and J′, R′, C′, n′, J″, R″, C″, n″ for CH4. The last column gives the upper and lower vibrational state in the notation of AFGL compilations.18,19
NH3 is NH3, CO2 is CO2, N2O is N2O, and H2O is H2O.
Table 3
Mean and rms Differencesa between Observed and Standard Positions
Region
Species
Mean (cm−1)
rms (cm−1)
Number of Lines
11 μm
NH3
−0.000 010
0.000 099
81
10 μm
CO2
−0.000 007
0.000 057
63
9 μm
N2O
−0.000 155
0.000 193
141
6 μm
H2O
−0.000 363
0.000 368
71
5 μm
CO
−0.000 431
0.000 431
12
3.3 μm
CH4
−0.000 032
0.000 032
1
2.2 μm
N2O
0.000 014
0.000 096
106
The mean and rms are computed using the observed minus the calculated line positions shown in Table 2.
Table 4
Band Constants of the 10°0–00°0 and 02°0–00°0 Bands of N2Oa
υ0
B
D × 107
H × 1013
Ground state
0.419 010 860(59)
1.760 625 (392)
−0.1781(924)
10°0–0000
1284.903 311(18)
0.417 255 194(50)
1.727 67(42)
1.6954(436)
02°0–0000
1168.132 300(27)
0.419 920 807(101)
2.491 61(120)
29.5350(1772)
The constants are in units of inverse centimeters.
Table 5
Calculated Line Positions of 2ν2 and ν1 of 14N216Oa
J
2ν2 (0200–0000)
ν1(1000–0000)
J
2ν2 (0200–0000)
ν1 (1000–0000)
P
R
P
R
P
R
P
R
0
1168.97214
1285.73782
26
1146.91751
1191.39245
1261.98739
1306.19071
1
1167.29428
1169.81379
1284.06529
1286.56881
27
1146.12336
1192.27372
1261.05980
1306.92913
2
1166.45808
1170.65725
1283.22376
1287.39629
28
1145.33058
1193.15603
1260.12884
1307.66395
3
1165.62371
1171.50251
1282.37873
1288.22024
29
1144.53912
1194.03935
1259.19453
1308.39518
4
1164.79117
1172.34955
1281.53020
1289.04066
30
1143.74895
1194.92362
1258.25686
1309.12281
5
1163.96045
1173.19837
1280.67818
1289.85756
31
1142.96003
1195.80880
1257.31585
1309.84684
6
1163.13155
1174.04894
1279.82266
1290.67091
32
1142.17232
1196.69484
1256.37150
1310.56727
7
1162.30448
1174.90125
1278.96367
1291.48073
33
1141.38578
1197.58168
1255.42382
1311.28410
8
1161.47922
1175.75529
1278.10119
1292.28701
34
1140.60038
1198.46929
1254.47281
1311.99734
9
1160.65576
1176.61103
1277.23524
1293.08974
35
1139.81607
1199.35760
1253.51849
1312.70697
10
1159.83409
1177.46845
1276.36581
1293.88892
36
1139.03281
1200.24656
1252.56086
1313.41300
11
1159.01421
1178.32753
1275.49293
1294.68455
37
1138.25055
1201.13614
1251.59993
1314.11543
12
1158.19610
1179.18824
1274.61658
1295.47662
38
1137.46927
1202.02627
1250.63571
1314.81426
13
1157.37975
1180.05056
1273.73677
1296.26514
39
1136.68890
1202.91690
1249.66820
1315.50949
14
1156.56514
1180.91447
1272.85352
1297.05009
40
1135.90942
1203.80798
1248.69742
1316.20112
15
1155.75224
1181.77992
1271.96682
1297.83148
41
1135.13077
1204.69947
1247.72337
1316.88915
16
1154.94106
1182.64689
1271.07668
1298.60930
42
1134.35292
1205.59130
1246.74606
1317.57358
17
1154.13155
1183.51535
1270.18311
1299.38355
43
1133.57582
1206.48343
1245.76550
1318.25441
18
1153.32370
1184.38527
1269.28611
1300.15423
44
1132.79943
1207.37581
1244.78171
1318.93165
19
1152.51749
1185.25660
1268.38568
1300.92133
45
1132.02370
1208.26838
1234.79468
1319.60529
20
1151.71289
1186.12932
1267.48184
1301.68485
46
1131.24860
1209.16110
1242.80444
1320.27533
21
1150.90987
1187.00338
1266.57459
1302.44479
47
1130.47407
1210.05391
1241.81098
1320.94178
22
1150.10841
1187.87875
1265.66394
1303.20115
48
1129.70009
1210.94677
1240.81432
1321.60464
23
1149.30847
1188.75538
1264.74988
1303.95392
49
1128.92660
1211.83963
1239.81447
1322.26392
24
1148.51003
1189.63324
1263.83243
1304.70311
50
1128.15357
1212.73244
1238.81144
1322.91961
25
1147.71306
1190.51227
1262.91160
1305.44871
The line positions in units of inverse centimeters are given with absolute accuracies of 0.0001 cm−1 and precisions of 0.000 04 cm−1.
The statistics reflect the precisions, not the absolute accuracies, of the band centers given in inverse centimeters. Ref. 8. Ref. 12. Ref. 4.
Adjusted using the value of Ref. 8 and a correction of −0.000 43 cm−1.
Computed value of 2–0 obtained by summing the reported values for the 1–0 and 2–1 bands of CO. Guelachvili’s measured value is 4 260.062 6413 cm−1.
Measured band center of 2–0 minus the computed values shown above.
The statistics represent the precisions, not the absolute accuracies, of the band centers given in inverse centimeters.
The ν3, ν1, and ν3–ν1 band centers are from Refs. 21, 11, and 20, respectively.
The expected value was obtained by subtracting the observed ν3 and ν1 values.
The difference in inverse centimeters between the expected and observed values.
Tables (7)
Table 1
Experimental Conditions of Calibration Spectrum
Absorption Cell
Species
Path (m)
Pressure (Torr)
6-m-base White cell
CO2
193
1.03
NH3
193
0.001
HCN
193
0.0005
2.4-m single pass
N2O
2.4
3.5
CH4
2.4
0.04
CO
2.4
0.005
Purged air path
H2O, CO2
∼8.0
∼0.1
FTS tank
H2O, CO2
10.0
∼0.01
Table 2
Comparison of Line Positions of NH3, CO2, H2O, CO, and CH4a
The line positions are in units of inverse centimeters. The literature values for NH3, CO2, N2O (at 9 μm), H2O, CO, CH4, and N2O (at 2.2 μm) have been taken from Refs. 15, 2, 11, 10, 8, 1, and 5, respectively. The rotational assignment consists of the upper state and lower state: J′, K′, J″, K″ for NH3; △J, J″ for CO2, CO, and N2O: J′, Ka′, Kc′, J″, Ka″, Kc″ for H2O; and J′, R′, C′, n′, J″, R″, C″, n″ for CH4. The last column gives the upper and lower vibrational state in the notation of AFGL compilations.18,19
NH3 is NH3, CO2 is CO2, N2O is N2O, and H2O is H2O.
Table 3
Mean and rms Differencesa between Observed and Standard Positions
Region
Species
Mean (cm−1)
rms (cm−1)
Number of Lines
11 μm
NH3
−0.000 010
0.000 099
81
10 μm
CO2
−0.000 007
0.000 057
63
9 μm
N2O
−0.000 155
0.000 193
141
6 μm
H2O
−0.000 363
0.000 368
71
5 μm
CO
−0.000 431
0.000 431
12
3.3 μm
CH4
−0.000 032
0.000 032
1
2.2 μm
N2O
0.000 014
0.000 096
106
The mean and rms are computed using the observed minus the calculated line positions shown in Table 2.
Table 4
Band Constants of the 10°0–00°0 and 02°0–00°0 Bands of N2Oa
υ0
B
D × 107
H × 1013
Ground state
0.419 010 860(59)
1.760 625 (392)
−0.1781(924)
10°0–0000
1284.903 311(18)
0.417 255 194(50)
1.727 67(42)
1.6954(436)
02°0–0000
1168.132 300(27)
0.419 920 807(101)
2.491 61(120)
29.5350(1772)
The constants are in units of inverse centimeters.
Table 5
Calculated Line Positions of 2ν2 and ν1 of 14N216Oa
J
2ν2 (0200–0000)
ν1(1000–0000)
J
2ν2 (0200–0000)
ν1 (1000–0000)
P
R
P
R
P
R
P
R
0
1168.97214
1285.73782
26
1146.91751
1191.39245
1261.98739
1306.19071
1
1167.29428
1169.81379
1284.06529
1286.56881
27
1146.12336
1192.27372
1261.05980
1306.92913
2
1166.45808
1170.65725
1283.22376
1287.39629
28
1145.33058
1193.15603
1260.12884
1307.66395
3
1165.62371
1171.50251
1282.37873
1288.22024
29
1144.53912
1194.03935
1259.19453
1308.39518
4
1164.79117
1172.34955
1281.53020
1289.04066
30
1143.74895
1194.92362
1258.25686
1309.12281
5
1163.96045
1173.19837
1280.67818
1289.85756
31
1142.96003
1195.80880
1257.31585
1309.84684
6
1163.13155
1174.04894
1279.82266
1290.67091
32
1142.17232
1196.69484
1256.37150
1310.56727
7
1162.30448
1174.90125
1278.96367
1291.48073
33
1141.38578
1197.58168
1255.42382
1311.28410
8
1161.47922
1175.75529
1278.10119
1292.28701
34
1140.60038
1198.46929
1254.47281
1311.99734
9
1160.65576
1176.61103
1277.23524
1293.08974
35
1139.81607
1199.35760
1253.51849
1312.70697
10
1159.83409
1177.46845
1276.36581
1293.88892
36
1139.03281
1200.24656
1252.56086
1313.41300
11
1159.01421
1178.32753
1275.49293
1294.68455
37
1138.25055
1201.13614
1251.59993
1314.11543
12
1158.19610
1179.18824
1274.61658
1295.47662
38
1137.46927
1202.02627
1250.63571
1314.81426
13
1157.37975
1180.05056
1273.73677
1296.26514
39
1136.68890
1202.91690
1249.66820
1315.50949
14
1156.56514
1180.91447
1272.85352
1297.05009
40
1135.90942
1203.80798
1248.69742
1316.20112
15
1155.75224
1181.77992
1271.96682
1297.83148
41
1135.13077
1204.69947
1247.72337
1316.88915
16
1154.94106
1182.64689
1271.07668
1298.60930
42
1134.35292
1205.59130
1246.74606
1317.57358
17
1154.13155
1183.51535
1270.18311
1299.38355
43
1133.57582
1206.48343
1245.76550
1318.25441
18
1153.32370
1184.38527
1269.28611
1300.15423
44
1132.79943
1207.37581
1244.78171
1318.93165
19
1152.51749
1185.25660
1268.38568
1300.92133
45
1132.02370
1208.26838
1234.79468
1319.60529
20
1151.71289
1186.12932
1267.48184
1301.68485
46
1131.24860
1209.16110
1242.80444
1320.27533
21
1150.90987
1187.00338
1266.57459
1302.44479
47
1130.47407
1210.05391
1241.81098
1320.94178
22
1150.10841
1187.87875
1265.66394
1303.20115
48
1129.70009
1210.94677
1240.81432
1321.60464
23
1149.30847
1188.75538
1264.74988
1303.95392
49
1128.92660
1211.83963
1239.81447
1322.26392
24
1148.51003
1189.63324
1263.83243
1304.70311
50
1128.15357
1212.73244
1238.81144
1322.91961
25
1147.71306
1190.51227
1262.91160
1305.44871
The line positions in units of inverse centimeters are given with absolute accuracies of 0.0001 cm−1 and precisions of 0.000 04 cm−1.
The statistics reflect the precisions, not the absolute accuracies, of the band centers given in inverse centimeters. Ref. 8. Ref. 12. Ref. 4.
Adjusted using the value of Ref. 8 and a correction of −0.000 43 cm−1.
Computed value of 2–0 obtained by summing the reported values for the 1–0 and 2–1 bands of CO. Guelachvili’s measured value is 4 260.062 6413 cm−1.
Measured band center of 2–0 minus the computed values shown above.
The statistics represent the precisions, not the absolute accuracies, of the band centers given in inverse centimeters.
The ν3, ν1, and ν3–ν1 band centers are from Refs. 21, 11, and 20, respectively.
The expected value was obtained by subtracting the observed ν3 and ν1 values.
The difference in inverse centimeters between the expected and observed values.