International Scholarly Research Notices

International Scholarly Research Notices / 2013 / Article

Research Article | Open Access

Volume 2013 |Article ID 592971 | 11 pages | https://doi.org/10.1155/2013/592971

Calculation of the Absorption Cross Sections of Some Molecules from GEISA Database at the Wavelengths of Isotopically Different CO2 Lasers

Academic Editor: Y. van der Burgt
Received08 Jul 2013
Accepted19 Sep 2013
Published26 Nov 2013

Abstract

A calculation of the absorption cross section of some molecules (NH3, C2H4, CO2, O3, NO2, PH3, HNO3, SF6, CH3OH, HCOOH, OCS, CH3CN, C2H6, SO2, and H2O) at the wavelengths transmitted by a CO2 laser filled with different isotopes (12C16O2, 13C16O2, 12C18O2, 14C16O2, 14C18O2, 13C18O2, and 12C16O18O) is presented. The spectroscopical parameters for the molecules from GEISA database have been used. Hence the selection of the molecules was substantially based on the availability of the parameters in the database. The results of the calculations may be used in designing the differential absorption technique for remote monitoring of these molecules. The pressure and temperature dependence of the cross sections are described by and coefficients; these coefficients were calculated for the largest absorption cross sections for each molecule. The absorption cross sections of CH3OH and HCOOH at low pressures for all these CO2 lasers are also presented. These calculations are provided for design of new CO2-laser-pumped far-infrared lasers.

1. Introduction

In this paper we report molecular absorption cross sections at CO2-laser emission frequencies for several selected gases of atmospheric relevance (M = NH3, C2H4, CO2, O3, NO2, PH3, HNO3, SF6, CH3OH, HCOOH, OCS, CH3CN, C2H6, SO2, and H2O). This information may be useful mainly in the differential absorption (Light Detection and Ranging) LIDAR technique for remote measurement of the gas species [18] and also may be used to monitor the CO2 content in fuel combustion products [9], remote sensing of gases in human breath [10], or multiphoton dissociation processes or to measure water vapor concentration and wind speed vector in the plume of volcano [11, 12]. Note that the LIDAR technique sometimes is used for remote sensing of some exotic gases, like, for example, chemical warfare [13].

In some cases (CH3OH and HCOOH) it also may be used in designing optically pumped FIR (far infrared=THz) lasers where CO2 laser is used as a source of a pump radiation [14]. Also, the absorption of CO2-laser radiation by a cell with a mixture of some of these gases is used in our lab for quick check and assignment of the CO2-laser lines.

The focus of the present study is to predict absorption cross section in pure air at wavelengths of seven isotopic CO2 lasers: 12C16O2 (normal), 13C16O2, 12C18O2, 14C16O2, 14C18O2, 13C18O2, and 12C16O18O, which we hereafter denote as 26-, 36-, 28-, 46-, 48-, 38-, and 268-lasers.

In the clear atmosphere, absorption at 9–11 μm is due primarily to water vapor and carbon dioxide. Since the fraction of CO2 in the atmosphere is about 3.8 × 10−4 and (CO2)~10−22 cm2, the resonant absorption of 50% of the 26-laser radiation by atmospheric molecules occurs at the distance about 7 km. This distance may be not large enough for typical LIDAR applications, like monitoring of air pollution over the large town or early detection of small forest fires [15, 16]. Also, the fluctuations of the CO2 concentration in the atmosphere decrease strongly the accuracy of the LIDAR based on the 26-laser. Hence the first advantage of latter six CO2 lasers over conventional 26-laser is low attenuation from atmospheric CO2, which may extend strongly the detection distance and/or the accuracy of the LIDAR. Moreover, these isotopically substituted CO2 lasers may be used to detect the concentration of CO2 in the atmosphere or, more simply, to monitor the CO2 content in fuel combustion products [9].

Another advantage is another set of wavelengths; sometimes it makes it possible to detect molecules, unavailable for conventional 26-laser LIDAR.

It is important to note that the use of CO2 lasers for LIDAR remote sensing offers some advantages over that of the more current LIDAR experiments being conducted using the fundamental absorption transitions of hydrocarbons near 3 to 4 μm and CW Quantum Cascade Lasers, in that the absorption values near 10 μm are not too high and not too low for remote sensing at ranges of a few hundred meters, and the output power of the CO2 laser is high offering good detection ranges.

Note that commercially available CO2 lasers often may be filled with different isotopic gases (e.g., PL3 series from Edinburgh Photonics). Also, CO2 lasers make up to 108 shots without changing of the gas mixture (e.g., InfraLight series of CO2 lasers); hence there is no large difference, which isotopic modification of CO2 gas to use.

This work was greatly facilitated by usage of GEISA spectroscopical database [17], and only the molecules from the database were involved in calculations. We have not included several gases (N2H4, C6H6, C2Cl4, C2HCl3, C2H3Cl, C2H5SH, C2H4Cl2, CF2Cl2, and CFCl3) which may be detected by CO2 lasers [18], since no information is available on their absorption cross sections in the GEISA and HITRAN databases.

There were a lot of experimental measurements of the absorption coefficients at 26-laser frequencies. The most popular molecules are SF6 [1921], C2H4 [2224], and NH3 [2226], and the list of references here is very large. A lot of for more complicated molecules are also reported in the literature, for example, for acetonitrile, benzene, cyclohexane, 1,2-dichloroethane, ethyl acetate, freon-12, freon-113, furan, isopropanol, methyl chloroform, methyl ethyl ketone, -butanol, vinyl chloride, and iodopropane [27]; seven hydrazine fuel gases [28]; hydrazine, unsymmetrical dimethylhydrazine, and monomethylhydrazine [29]; C2H4, C2H3Cl3, C2HCl3, and Freon-113 [3]; and triacetone triperoxide [8].

However, much less information is available regarding of CO2 lasers other than 26-laser. For example, we know the measurements of (H2O) at 26-, 36-, and 46-laser wavelengths [30], (ClO2) at 28-laser wavelengths [31], (NH3) at a 36-laser [32]. Also, the photoacoustic spectroscopy has been used to determine for M = NH3, CCl2F2, CHClF2, CFCl3, and CClF3 at 36-laser wavelengths [33].

To the best of our knowledge, the FIR lasers normally are pumped by 26-lasers or, much rarely, by 36-laser [3437]; the other CO2 lasers are used very rarely [38, 39]. Note that while 26-laser has about 100 laser lines, using different isotopic CO2 lasers gives up to 1000 lines; hence the amount of different FIR-lasers pumped by CO2 lasers should increase accordingly.

With this in mind, we performed the calculation which hopefully provides the information of the quality comparable with that of the experimental studies. We hope that it will stimulate using isotopically different CO2 lasers for different applications.

2. Results

Assuming Lorentzian line shapes, we calculated the absorption cross sections at all possible CO2-laser frequencies. Tables 1, 2, and 3 show for 26-, 36-, and 28-lasers, respectively, for CO2-laser lines between P(40) and R(40), excluding the range P(6)–R(6). Atmospheric pressure bar and temperature  K are assumed everywhere, and the self-broadening is neglected (i.e., [M]≪[air]). The following expressions were used: where the index labels all transitions in molecule , is intensity of the th spectral line, , is Lorentzian width, , is the absorption maximum frequency of the th spectral line, is the pressure shift of the line transition, is the energy of the lower state for th transition, for linear molecules like CO2 and for nonlinear molecules, and are air pressure and temperature, respectively, and is Boltzmann constant.


Line 00°1 → 10°0, 10.4  ma 00°1 → 02°0, 9.4  mb
, cm−1CO2 NH3C2H4CH3OH O3 PH3HNO3 SF6 H2O , cm−1CO2 NH3C2H4CH3OH HCOOH O3 PH3 H2O

P(40) 924.97398 0.0019 3.73 2.12 0.006 0.003 0.262 2.91 1.38 3.2576 1027.38217 0.0030 7.67 2.58 15.9 1.01 21.7 0.316 0.0753
P(38) 927.00832 0.0025 16.5 7.86 0.006 0.003 0.075 1.95 1.68 0.0065 1029.44209 0.0038 0.656 3.45 12.8 1.26 32.6 0.446 1.1490
P(36) 929.01744 0.0030 32.9 4.66 0.006 0.004 0.053 1.31 2.10 0.4532 1031.47743 0.0048 2.18 1.68 28.5 1.47 27.1 15.5 0.0072
P(34) 931.00143 0.0039 55.2 5.91 0.007 0.004 0.028 0.892 2.69 0.0023 1033.48800 0.0059 13.5 7.19 103 3.00 13.3 2.08 0.0056
P(32) 932.96042 0.0046 57.6 4.42 0.007 0.004 0.105 0.627 3.57 0.0092 1035.47362 0.0070 0.930 2.36 8.62 1.06 19.8 0.318 0.0027
P(30) 934.89450 0.0054 3.33 6.12 0.007 0.005 0.375 0.476 5.03 0.0041 1037.43411 0.0083 0.234 4.97 6.20 1.10 22.8 1.76 0.0103
P(28) 936.80375 0.0065 1.06 4.95 0.008 0.005 1.34 0.402 8.01 0.0035 1039.36931 0.0096 0.198 0.77 4.30 1.43 32.7 1.80 0.0583
P(26) 938.68826 0.0072 1.02 7.86 0.008 0.006 0.225 0.268 16.1 0.2236 1041.27907 0.0109 0.391 0.81 15.8 1.01 21.5 7.94 0.0163
P(24) 940.54810 0.0079 0.364 8.62 0.009 0.007 0.036 0.204 42.5 0.0205 1043.16324 0.0121 0.915 1.26 15.0 1.64 2.71 5.99 0.0134
P(22) 942.38334 0.0086 0.245 5.38 0.009 0.008 0.037 0.159 119 0.0049 1045.02167 0.0134 1.62 3.04 25.3 3.28 7.20 16.2 0.0122
P(20) 944.19403 0.0094 0.347 7.63 0.010 0.009 5.45 0.131 262 0.0106 1046.85423 0.0138 13.2 1.54 14.8 2.10 16.9 4.44 0.0045
P(18) 945.98023 0.0095 0.395 13.8 0.010 0.010 5.72 0.104 349 0.0150 1048.66081 0.0142 1.06 2.88 29.3 1.64 23.3 6.28 0.0148
P(16) 947.74198 0.0094 2.30 21.4 0.011 0.015 0.134 0.079 862 0.1346 1050.44128 0.0142 0.702 0.69 29.7 1.85 32.8 0.88 0.0202
P(14) 949.47931 0.0092 1.84 133 0.011 0.013 0.030 0.060 412 0.0261 1052.19555 0.0137 1.40 0.47 48.6 2.06 47.4 8.53 0.0030
P(12) 951.19226 0.0085 2.57 17.3 0.012 0.026 0.079 0.046 354 0.0054 1053.92350 0.0128 3.70 0.47 24.8 2.43 44.0 4.62 0.0022
P(10) 952.88085 0.0075 0.675 13.0 0.013 0.022 0.045 0.037 67.9 0.0038 1055.62507 0.0118 1.08 1.28 30.8 3.70 23.0 3.14 0.0040
P(8) 954.54509 0.0063 1.01 5.83 0.014 0.030 4.30 0.032 22.3 0.0431 1057.30016 0.0096 0.208 2.94 26.5 3.14 49.2 2.10 0.0048
P(6) 956.18498 0.0049 2.86 7.96 0.015 0.043 3.78 0.027 12.2 0.0093 1058.94871 0.0073 0.377 1.18 39.0 4.65 34.4 3.42 0.0804
R(6) 966.25036 0.0057 124 7.99 0.030 0.088 0.284 0.011 2.07 0.0159 1069.01409 0.0086 0.541 1.24 11.5 10.6 2.93 1.48 0.0317
R(8) 967.70723 0.0071 102 3.68 0.037 0.128 0.255 0.010 1.76 0.0088 1070.46231 0.0108 7.04 1.33 11.1 13.3 1.76 1.71 0.0978
R(10) 969.13955 0.0083 2.62 5.26 0.059 0.150 0.099 0.010 1.53 0.0068 1071.88377 0.0125 0.972 1.47 9.16 16.6 0.871 9.28 0.0344
R(12) 970.54724 0.0092 1.09 7.58 0.679 0.160 0.127 0.009 1.34 0.3381 1073.27848 0.0139 1.12 0.391 7.25 16.6 0.749 4.55 0.1450
R(14) 971.93026 0.0097 27.6 6.51 1.44 0.215 0.844 0.009 1.18 0.0225 1074.64649 0.0149 2.37 0.257 5.15 23.0 0.616 3.91 0.0539
R(16) 973.28852 0.0099 0.485 3.76 1.60 0.286 0.234 0.009 1.06 0.1583 1075.98782 0.0153 52.1 1.12 4.39 27.0 0.470 2.07 3.2810
R(18) 974.62194 0.0098 0.270 2.39 0.81 0.397 0.834 0.008 0.953 0.0270 1077.30252 0.0152 0.450 2.17 4.28 29.5 0.351 4.00 0.0822
R(20) 975.93044 0.0095 0.193 4.70 3.33 0.429 0.868 0.008 0.864 3.3148 1078.59064 0.0147 0.226 0.520 2.23 33.8 0.408 1.15 0.0213
R(22) 977.21392 0.0089 0.152 12.7 1.78 0.377 0.574 0.008 0.789 0.0128 1079.85226 0.0139 0.225 0.289 2.01 35.1 0.494 1.60 0.0118
R(24) 978.47229 0.0081 0.126 19.3 2.09 0.491 0.846 0.008 0.725 0.0044 1081.08743 0.0134 0.274 0.689 0.718 47.8 0.820 3.53 0.0127
R(26) 979.70542 0.0073 0.109 8.84 3.68 0.520 0.618 0.007 0.669 0.0028 1082.29624 0.0116 0.511 0.276 0.622 35.5 0.446 0.55 0.0829
R(28) 980.91321 0.0063 0.098 10.3 1.32 0.639 3.51 0.007 0.620 0.0054 1083.47878 0.0102 1.90 0.101 0.394 59.4 0.443 0.36 0.0587
R(30) 982.09553 0.0054 0.092 1.47 4.58 0.674 4.60 0.007 0.578 0.0123 1084.63514 0.0089 303 0.671 0.687 57.1 0.359 0.73 0.6919
R(32) 983.25225 0.0046 0.089 3.91 2.91 1.65 8.01 0.007 0.540 0.0046 1085.76544 0.0077 2.35 0.183 0.068 47.1 0.351 5.23 0.0261
R(34) 984.38323 0.0037 0.090 2.39 8.29 0.823 4.43 0.006 0.507 0.0246 1086.86979 0.0062 0.945 0.134 0.053 59.6 0.304 1.35 0.0098
R(36) 985.48831 0.0030 0.097 10.7 3.93 1.05 5.83 0.006 0.478 0.0036 1087.94831 0.0051 0.403 1.39 0.046 54.1 0.533 5.94 0.3016
R(38) 986.56735 0.0024 0.116 14.7 9.68 1.21 2.94 0.006 0.451 0.0104 1089.00112 0.0041 1.73 0.109 0.041 69.9 0.299 0.53 0.0072
R(40) 987.62018 0.0019 0.574 18.8 5.04 1.42 2.12 0.006 0.427 0.1652 1090.02837 0.0036 0.672 0.252 0.038 65.5 0.507 3.16 0.0054

aCross sections for HCOOH are omitted; (HCOOH) 0−21 cm2.
bCross sections for HNO3 and SF6 are omitted; (HNO3) 0−23 cm2; and (SF6) 0−21 cm2.

Line 00°1 10°0, 11  ma 00°1 02°0, 10  mb
, cm−1 CO2 NH3C2H4 PH3HNO3 SF6H2O , cm−1CO2 NH3C2H4CH3OH HCOOH O3 PH3 SF6 H2O

P(40) 878.43359 0.00003 0.056 3.55 0.823 69.6 0.142 1.6272 980.80503 0.00190 0.099 6.85 1.32 0.051 0.603 1.32 0.625 0.0045
P(38) 880.37051 0.00005 0.055 2.93 0.413 26.7 0.150 0.0211 982.91254 0.00026 0.089 5.95 1.57 0.052 0.736 0.887 0.551 0.0054
P(36) 882.28741 0.00006 0.074 4.07 0.029 33.3 0.159 0.0222 984.99314 0.00015 0.093 4.92 2.11 0.053 0.764 2.58 0.490 0.0044
P(34) 884.18435 0.00005 0.111 2.59 0.026 37.1 0.169 0.1661 987.04662 0.00013 0.139 11.5 2.53 0.085 1.04 2.84 0.440 0.0455
P(32) 886.06142 0.00006 0.327 5.11 0.037 32.9 0.179 0.0348 989.07282 0.00010 0.251 1.61 2.88 0.099 1.82 19.1 0.398 0.0089
P(30) 887.91867 0.00009 58.5 5.77 0.026 38.5 0.190 0.0968 991.07153 0.00008 1.56 3.09 3.49 0.086 1.48 2.31 0.362 0.0085
P(28) 889.75616 0.00008 0.515 6.16 0.228 48.6 0.203 0.0461 993.04260 0.00008 10.1 2.16 4.57 0.110 3.81 7.59 0.331 0.0022
P(26) 891.57394 0.00009 4.53 2.93 0.312 40.8 0.216 0.0541 994.98585 0.00011 0.354 5.15 6.55 0.124 3.16 0.908 0.304 0.0037
P(24) 893.37207 0.00010 0.640 1.91 0.405 35.3 0.231 0.0037 996.90115 0.00008 0.143 22.1 8.66 0.128 5.04 0.736 0.280 0.0016
P(22) 895.15057 0.00013 0.157 3.09 0.389 50.6 0.247 0.0057 998.78832 0.00009 0.100 3.94 14.8 0.282 3.44 0.068 0.260 0.0028
P(20) 896.90948 0.00016 0.087 7.85 0.017 33.7 0.265 0.0036 1000.64726 0.00009 0.095 8.23 23.4 0.204 6.96 3.15 0.242 0.0364
P(18) 898.64883 0.00015 0.072 2.55 0.016 33.4 0.284 0.0017 1002.47781 0.00008 0.185 3.63 27.0 0.281 6.64 0.166 0.226 0.0033
P(16) 900.36865 0.00027 0.406 3.49 0.447 30.2 0.305 0.0018 1004.27987 0.00008 0.197 7.15 27.8 0.253 10.2 2.92 0.212 0.0282
P(14) 902.06895 0.00015 0.109 8.26 0.596 24.1 0.329 0.0037 1006.05332 0.00008 1.14 11.4 28.3 0.291 12.4 0.259 0.199 0.0020
P(12) 903.74974 0.00012 0.134 2.11 0.490 21.3 0.354 0.0039 1007.79807 0.00021 19.3 6.77 26.1 0.386 10.7 0.204 0.188 0.0054
P(10) 905.41104 0.00014 0.253 5.76 0.075 26.4 0.383 0.0183 1009.51402 0.00007 0.699 6.54 18.4 0.392 17.5 0.340 0.177 0.0105
P(8) 907.05284 0.00009 1.17 1.43 1.347 22.1 0.415 0.0379 1011.20110 0.00006 58.0 5.34 23.2 0.423 8.58 2.23 0.168 0.0639
P(6) 908.67515 0.00011 6.65 18.5 0.034 19.4 0.451 0.6599 1012.85922 0.00005 7.21 2.47 19.8 0.597 10.1 0.099 0.159 0.0031
R(6) 918.74396 0.00080 5.33 4.27 0.182 9.07 0.830 0.0581 1022.92804 0.00016 0.425 2.44 10.8 0.648 29.2 0.563 0.120 0.0169
R(8) 920.21948 0.00014 1.01 2.49 0.027 8.22 0.924 0.0159 1024.36774 0.00009 0.315 4.54 18.3 0.693 30.6 9.46 0.115 2.0415
R(10) 921.67529 0.00020 3.94 6.48 0.047 5.97 1.04 0.1895 1025.77827 0.00013 0.688 2.01 12.1 0.804 18.5 1.61 0.111 0.0241
R(12) 923.11133 0.00034 2.35 7.93 3.736 4.15 1.17 0.0353 1027.15966 0.00036 40.1 11.1 14.1 1.01 27.3 1.05 0.107 0.0417
R(14) 924.52755 0.00019 2.12 5.52 4.968 3.16 1.32 0.0856 1028.51193 0.00014 0.657 1.92 10.9 1.29 39.6 0.293 0.103 0.2480
R(16) 925.92391 0.00016 11.1 5.39 1.391 2.50 1.51 0.0223 1029.83513 0.00022 1.22 2.59 11.6 1.32 24.4 4.35 0.100 0.1042
R(18) 927.30032 0.00028 119 2.81 0.166 1.83 1.73 0.0060 1031.12930 0.00029 1.45 2.17 25.2 1.59 23.8 1.31 0.097 0.0084
R(20) 928.65672 0.00028 48.6 3.72 0.033 1.40 2.01 0.0151 1032.39450 0.00021 9.72 3.79 52.2 1.71 34.6 3.37 0.094 0.0245
R(22) 929.99305 0.00017 61.6 7.50 0.159 1.04 2.36 0.0048 1033.63081 0.00118 8.69 2.87 98.2 2.29 16.0 1.48 0.091 0.0048
R(24) 931.30921 0.00031 92.2 6.99 0.026 0.858 2.80 0.0020 1034.83829 0.00032 3.15 0.822 11.3 1.10 41.4 0.571 0.089 0.0033
R(26) 932.60512 0.00033 29.0 3.83 0.064 0.699 3.38 0.0037 1036.01703 0.00023 0.522 1.90 9.385 1.32 22.8 0.586 0.087 0.0031
R(28) 933.88070 0.00035 12.9 4.32 4.787 0.519 4.16 0.0018 1037.16713 0.00063 0.259 4.61 6.56 1.01 18.4 1.12 0.084 0.0056
R(30) 935.13584 0.00054 3.89 2.31 0.778 0.407 5.29 0.0093 1038.28870 0.00019 0.187 2.46 8.77 1.29 23.7 7.02 0.082 0.5229
R(32) 936.37044 0.00028 1.83 4.27 0.305 0.356 7.09 0.0076 1039.38184 0.00934 0.201 0.755 4.29 1.35 32.5 1.70 0.080 0.0622
R(34) 937.58440 0.00029 4.36 7.51 0.100 0.345 10.3 0.0092 1040.44668 0.00036 0.206 1.79 9.24 0.92 28.3 1.31 0.079 0.3301
R(36) 938.77760 0.00287 0.711 8.95 0.122 0.297 16.7 0.0647 1041.48333 0.00122 0.258 1.50 11.7 1.61 21.1 5.00 0.077 0.0152
R(38) 939.94992 0.00021 0.290 8.38 0.020 0.239 30.3 0.0094 1042.49195 0.00045 0.276 1.33 7.18 2.44 3.34 0.876 0.075 0.9977
R(40) 941.10124 0.00023 0.352 9.78 0.020 0.181 58.7 0.3694 1043.47268 0.00068 0.450 1.45 19.0 1.81 2.85 1.22 0.074 0.0074

aCross sections for CH3OH, HCOOH, and O3 are omitted; (CH3OH)  cm2; (HCOOH)  cm2, and (O3)  cm2.
bCross sections for HNO3 are omitted; (HNO3)  cm2.

Line 00°1 10°0, 10.5  ma 00°1 02°0, 9  mb
, cm−1CO2 NH3C2H4CH3OH O3 PH3HNO3 SF6 H2O , cm−1 CO2 NH3C2H4CH3OH HCOOH O3 PH3 H2O

P(40) 933.98651 0.00023 7.92 3.30 0.007 0.004 1.81 0.553 4.24 0.0019 1052.26317 0.00763 1.41 0.495 45.8 2.24 59.2 4.32 0.0027
P(38) 935.88894 0.00013 14.9 2.92 0.008 0.005 0.217 0.388 6.27 0.0070 1054.01438 0.00542 5.55 0.354 24.1 3.24 39.3 2.96 0.0021
P(36) 937.76432 0.00014 2.43 5.59 0.008 0.006 0.143 0.279 11.0 0.0056 1055.74733 0.00352 0.755 0.775 26.8 3.49 35.0 4.43 0.0047
P(34) 939.61272 0.00022 0.586 8.01 0.008 0.006 0.023 0.224 25.3 0.0054 1057.46193 0.00235 0.194 2.37 33.8 4.15 29.9 2.79 0.0052
P(32) 941.43421 0.00020 0.313 7.15 0.009 0.007 0.021 0.170 70.9 0.0357 1059.15808 0.00168 0.187 1.61 27.5 5.50 26.6 17.3 0.3398
P(30) 943.22886 0.00020 0.291 8.33 0.009 0.009 0.094 0.121 180 0.0044 1060.83568 0.00090 0.178 0.436 28.0 4.57 21.4 0.785 0.0601
P(28) 944.99673 0.00019 0.341 10.0 0.010 0.013 4.10 0.100 319 0.2328 1062.49464 0.00040 0.277 0.547 28.3 6.06 36.7 3.25 0.0111
P(26) 946.73787 0.00039 0.435 16.5 0.010 0.014 0.139 0.075 418 0.1333 1064.13489 0.00024 1.01 0.686 18.2 6.45 9.19 4.82 0.0116
P(24) 948.45233 0.00022 8.59 31.7 0.011 0.014 0.052 0.059 473 0.9095 1065.75632 0.00046 48.1 0.731 21.7 8.65 15.0 0.723 0.1324
P(22) 950.14015 0.00022 0.772 51.2 0.012 0.019 0.021 0.049 476 0.0190 1067.35888 0.00124 1.32 0.523 15.3 12.3 4.85 2.05 0.0094
P(20) 951.80137 0.00023 44.0 14.6 0.013 0.017 0.025 0.040 215 0.0042 1068.94248 0.00500 0.576 1.42 12.4 9.70 3.14 0.949 0.0393
P(18) 953.43603 0.00022 0.402 7.47 0.013 0.025 0.112 0.035 42.0 0.0048 1070.50705 0.00822 11.1 1.42 10.4 13.1 1.71 2.21 0.0788
P(16) 955.04415 0.00022 0.905 11.7 0.014 0.026 0.990 0.030 18.1 0.1436 1072.05253 0.00232 1.15 3.79 10.1 19.7 0.596 2.09 0.0436
P(14) 956.62576 0.00022 0.909 7.80 0.015 0.041 0.246 0.027 10.8 0.0051 1073.57887 0.00101 1.55 0.617 6.17 17.0 0.388 4.11 0.0368
P(12) 958.18087 0.00019 2.76 6.31 0.017 0.040 0.142 0.018 7.31 0.0033 1075.08599 0.00063 9.99 0.250 6.53 21.7 0.890 8.62 0.0940
P(10) 959.70950 0.00015 6.090 7.24 0.018 0.040 0.063 0.016 5.34 0.1043 1076.57386 0.00053 1.62 0.316 3.47 25.7 0.382 1.33 0.6481
P(8) 961.21166 0.00006 10.7 3.56 0.020 0.058 0.087 0.017 4.10 0.0092 1078.04242 0.00056 0.262 0.227 2.65 30.2 0.337 1.21 0.0334
P(6) 962.68734 0.00009 16.0 4.63 0.022 0.077 0.053 0.013 3.27 0.0161 1079.49163 0.00077 0.541 0.973 1.73 37.8 0.352 0.538 0.0132
R(6) 971.63344 0.00066 5.32 2.18 1.60 0.305 0.376 0.009 1.22 0.0693 1088.43774 0.00069 0.500 0.118 0.044 68.5 0.474 0.460 0.0092
R(8) 972.91019 0.00046 0.671 3.69 1.18 0.315 0.889 0.009 1.09 0.0253 1089.74096 0.00046 1.71 0.748 0.039 62.8 0.349 0.461 0.0069
R(10) 974.16030 0.00035 0.315 2.27 1.42 0.257 4.12 0.009 0.98 0.13597 1091.02466 0.00256 0.494 0.345 0.035 64.7 0.341 2.60 0.0203
R(12) 975.38372 0.00029 0.219 10.3 1.86 0.223 0.855 0.008 0.89 0.06139 1092.28884 0.00039 0.682 0.061 0.032 58.1 0.239 1.75 0.0056
R(14) 976.58041 0.00028 0.170 6.73 1.12 0.322 0.935 0.008 0.82 0.04755 1093.53351 0.00028 3.06 0.670 0.029 60.9 0.245 0.184 0.0064
R(16) 977.75031 0.00028 0.139 7.77 3.71 0.344 2.88 0.008 0.76 0.00860 1094.75869 0.00068 1.64 0.654 0.027 49.7 0.546 0.205 0.0159
R(18) 978.89336 0.00031 0.119 18.3 1.15 0.669 1.80 0.007 0.70 0.00365 1095.96438 0.00008 3.93 0.080 0.025 55.0 0.259 1.73 0.0256
R(20) 980.00950 0.00043 0.106 2.27 4.07 0.569 0.884 0.007 0.65 0.00286 1097.15060 0.00006 0.610 0.200 0.024 41.3 0.306 0.702 0.0127
R(22) 981.09866 0.00082 0.097 3.50 1.43 0.766 2.86 0.007 0.61 0.00823 1098.31739 0.00005 0.336 0.538 0.022 38.0 0.284 0.640 0.0109
R(24) 982.16077 0.00287 0.091 1.83 5.35 0.581 2.51 0.007 0.57 0.00986 1099.46477 0.00005 0.219 0.076 0.021 28.0 0.343 0.308 0.0319
R(26) 983.19575 0.00273 0.089 3.92 2.40 1.03 7.74 0.007 0.54 0.00442 1100.59277 0.00006 0.245 0.181 0.020 20.5 0.211 0.424 0.1863
R(28) 984.20351 0.00052 0.090 2.43 5.30 1.04 1.77 0.007 0.51 0.13352 1101.70143 0.00005 0.528 0.367 0.019 15.1 0.338 0.309 0.2239
R(30) 985.18397 0.00020 0.094 2.22 3.01 0.648 1.70 0.006 0.48 0.00385 1102.79079 0.00001 3.34 0.058 0.018 12.9 0.112 0.245 0.0393
R(32) 986.13704 0.00011 0.106 17.3 7.81 2.00 1.62 0.006 0.46 0.00541 1103.86091 0.00001 8.85 0.690 0.017 26.7 0.403 1.41 0.0131
R(34) 987.06260 0.00012 0.140 11.4 2.51 1.08 2.61 0.006 0.44 0.04930 1104.91182 0.00001 0.871 0.113 0.017 228 0.231 0.298 0.0123
R(36) 987.96056 0.00011 0.339 27.6 6.97 1.49 3.63 0.006 0.42 0.02590 1105.94358 0.00001 0.313 0.366 0.016 102 0.177 0.267 0.0115
R(38) 988.83081 0.00020 0.309 3.26 4.97 2.32 10.2 0.006 0.40 0.11022 1106.95625 0.00001 0.248 0.099 0.015 36.9 0.154 1.43 0.0145
R(40) 989.67323 0.00093 0.315 6.78 5.73 1.26 9.46 0.006 0.38 0.00456 1107.94989 0.00000 3.61 0.181 0.015 26.3 0.293 0.682 0.0275

aCross sections for HCOOH are omitted; (HCOOH)  cm2.
bCross sections for HNO3 and SF6 are omitted; (HNO3)  cm2 and (SF6)  cm2.

The parameters , , , , , and are taken from GEISA database for each transition of each M molecule. Note that the pressure shifts are given in the database only for CH3CN and NO2 molecules. All of them are rather small (10−3 cm−1/atm), and they change only the third digit in calculated absorption cross sections. We hope that there is the same situation with all other molecules; hence we present the cross sections with three-digit accuracy; the last digit may be wrong due to the pressure shifts. All CO2-laser frequencies were taken from Freed et al. [40].

In Table 4 we present the “best” laser transitions for each isotopic variation of CO2 laser and for each molecule M. The pressure and temperature dependence of the cross sections are described by and coefficients as , , and the coefficients have been calculated from (1) and presented in Table 4 also.


Laser M Transition , cm−1σ(M)a

26 NH3 10R(30) 1084.63514 303 0.38
C2H4 11P(14) 949.47931 133 0.16
O3 10P(14) 1052.19555 47.4 0.08
10P(8) 1057.30016 49.2*
NO2 11P(48) 916.58177 0.143 3.11
PH3 10P(22) 1045.02167 16.2
HNO3 11P(44) 920.82912 6.89 1.90
SF6 11P(16) 947.74198 862
CH3OH 10P(34) 1033.48800 103 0.44
HCOOH 10R(28) 1083.47878 59.4 0.37
OCS 10P(32) 1035.47362 1.68
CH3CN 10R(16) 1075.98782 1.82 1.38
SO2 10R(26) 1082.29624 0.430 2.26
SO2 10R(40) 1090.02837 0.595* 1.54 0.15
H2O 11R(20) 975.93044 0.00331 6.47

36 NH3 11R(18) 927.30032 119 0.57
C2H4 10P(24) 996.90115 22.1
CO2 10R(32) 1039.38184 0.009 7.45
O3 10R(24) 1034.83829 41.4
NO2 11P(38) 880.37051 0.461 1.43
PH3 10P(32) 989.07282 19.1 0.92
HNO3 11P(22) 895.15057 50.6 0.36
11P(40) 878.43359 69.6* 0.26 0.05
SF6 11R(42) 942.23141 110 0.87 0.14
11R(44) 943.34030 189* 0.38 0.02
CH3OH 10R(22) 1033.63081 98.2 0.45
HCOOH 10R(38) 1042.49195 2.44 1.22
OCS 10R(36) 1041.48333 2.08
CH3CN 10R(10) 1025.77827 2.86 0.23 0.01
C2H6 11P(48) 870.48389 0.493 0.85 0.06
H2O 9R(8) 1024.36774 0.00204 6.41 0.65

28 NH3 11P(20) 951.80137 44.0
11P(42) 932.05695 67.9*
C2H4 11P(22) 950.14015 51.2 0.49 0.04
CO2 10P(18) 1070.50705 0.008 5.22
10P(44) 1048.70641 0.010* 6.19
O3 10P(40) 1052.26317 59.2*
10P(36) 1055.74733 35.0 0.04
NO2 11P(42) 932.05695 0.021* 2.86
11P(34) 939.61272 0.013 3.56
PH3 10P(32) 1059.15808 17.3 0.58
HNO3 11P(34) 939.61272 0.224 2.39 0.20
11P(42) 932.05695 0.756* 2.57 0.03
SF6 11P(22) 950.14015 476
CH3OH 10P(40) 1052.26317 45.8 0.42
HCOOH 10R(34) 1104.91182 228
OCS 10P(28) 1062.49464 2.06 0.54
CH3CN 10P(32) 1059.15808 3.74
SO2 10R(36) 1105.94358 1.73 0.80
H2O 11P(24) 948.45233 0.000910 4.62 0.79

46 NH3 9P(18) 967.44673 151
C2H4 9P(36) 949.82361 75.5 0.55
CO2 9P(38) 947.72257 0.009 6.83
O3 9R(38) 1007.32003 14.4 1.51
NO2 10R(18) 880.14964 0.617 1.99
PH3 9R(12) 992.16155 20.1 0.42
HNO3 10R(16) 878.74397 116 0.00
SF6 9P(38) 947.72257 860
CH3OH 9R(36) 1006.33091 31.1 0.96
HCOOH 9R(40) 1008.28028 0.572 0.85
OCS 10R(14) 877.32170 2.41 1.16
CH3CN 9R(16) 994.82189 0.839 1.88
C2H6 10P(4) 862.98995 0.666 0.98
H2O 11R(16) 878.74397 0.000532 4.97 0.77

38 NH3 10R(10) 1034.18567 86.9
C2H4 11R(34) 949.30088 121 0.14
CO2 10R(32) 1046.81398 0.011 6.41
O3 10R(14) 1036.67254 33.4
10R(8) 1032.91023 38.3*
10R(40) 1050.77747 50.5*
NO2 11P(16) 916.81456 0.134 2.86
PH3 10R(22) 1041.39099 11.3
10R(6)
1031.61345 13.9*
HNO3 11P(38) 898.25437 35.3 0.43
11P(40) 896.42949 53.4*
SF6 11R(30) 947.29249 641
CH3OH 10R(10) 1034.18567 66.3 0.16
10R(8) 1032.91023 81.5* 0.79
HCOOH 10R(24) 1042.51764 2.50 1.22
10R(40) 1050.77747 4.01* 1.15
OCS 10R(12) 1035.43977 1.98 0.08
CH3CN 10R(34) 1047.83586 3.57
SO2 10R(46) 1053.53509 0.024 4.78 0.00
H2O 11R(32) 948.30848 0.00577 5.06

48 NH3 9P(20) 967.55794 79.2 0.56
C2H4 9P(40) 950.27719 38.0 0.31 0.19
CO2 9P(18) 969.16198 0.008 6.48
O3 9R(32) 1002.18855 11.4 2.01
9R(40) 1006.00000 11.8* 1.68
NO2 10P(12) 880.59011 0.159 1.00 0.08
PH3 9R(14) 992.26858 21.3
HNO3 10P(14) 879.08844 90.0
SF6 9P(40) 950.27719 476
9P(42) 948.42788 484* 0.20
CH3OH 9R(36) 1004.13958 28.9 1.23
HCOOH 9R(34) 1003.17544 0.365 1.63
OCS 10P(30) 866.40889 6.03
CH3CN 10R(28) 907.29104 0.559
C2H6 10P(36) 861.34626 0.777 0.46
H2O 11P(24) 871.30294 0.00549 4.02

268 NH3 10P(32) 1046.35094 264
C2H4 11P(21) 949.43752 149 0.23
CO2 10R(11) 1081.07931 0.013 7.17
O3 10P(27) 1050.83825 56.6
NO2 11P(37) 934.69411 0.067 3.71 0.03
PH3 11R(36) 988.95058 19.8 1.33
11R(42) 991.76694 38.6* 0.02
HNO3 11P(50) 921.46702 6.33 2.00
SF6 11P(23) 947.68595 851 0.00
CH3OH 10P(46) 1033.08142 95.5 0.73
HCOOH 10R(24) 1089.24975 77.9
OCS 10P(16) 1060.23019 2.20 0.14
CH3CN 10P(24) 1053.46560 2.92
SO2 10R(36) 1095.95040 1.03 1.38
H2O 9R(16) 1084.33484 0.00439 5.37 0.21

aAsterisk marks the cases where the (M) is large, but the CO2 laser line is marginal. The values below  cm2 are omitted.

It is not easy task to point out the “best” CO2-laser line for detection of molecule M. Normally the “best” CO2-laser line should lie in the ranges R(10)–R(40), P(10)–P(40) and has the largest absorption by M molecules; if the largest values occur outside these ranges, we mark it by asterisk shown in the table also. However, if the largest values occur at marginal lines of CO2 laser and are much larger than all other cross sections, we present this marginal line only.

3. Discussion

Some of our results are compared with the experimental literature data in Table 5. As one can see from the table, the present results agree favorably with the experimental data of Patty et al. [24] and Persson et al. [22], who have determined , , and coefficients for 26-laser absorption by NH3, O3, and C2H4 molecules.


M Laser line , cm−1 (M), 10−20 cm2
[24] [22] a [22] a [22] a

NH3 9R(16) 1075.98782 51.6 c 52.1 c 0.70 c
11R(8) 967.70723 88.9 92.6 102
11R(14) 971.93026 2.56b30.2 27.6
11P(32) 932.96042 60.9 c 57.6 c 0.03 c
11P(34) 931.00143 50.3 c 55.2 c c 0.60
9R(30) 1084.63514 c c 303 c 0.38 c
9P(20) 1046.85423 8.77 12.1 13.2 0.96 0.92

C2H411P(14) 949.47931 118.4 145.1 133 0.16 0.03
11P(16) 947.74198 c 23.9 21.4 0.01
11R(24) 978.47229 20.5 20.9 19.3
11P(12) 951.19226 c 19.7 17.3 0.30 0.42

O3 9P(14) 1052.19555 51.6 c 47.4 c c 0.08
9P(12) 1053.92350 49.5 c 44.0 c c
9P(8) 1057.30016 51.6 c 49.2 c c

aThis work.
bProbably, misprint.
cNo data.

Note that only in several cases our M molecules are important as “standard” air pollutant (NH3, C2H4, PH3, and O3) and in other cases our M molecules may happen in the air only near special industrial objects. As one can see from Tables 14, 26-laser is a good choice for all these four gases.

There are several advantages of the other CO2 lasers: monitoring of HNO3, NO2, C2H6, and CO2 molecules requires 46-/48-/36-, 36-, 36-/46-/48-, and 38-/268-lasers, respectively, instead of 26-laser.

We included in Table 4 several molecules with low cross sections (OCS, CH3CN, C2H6, SO2, and NO2). Although CO2 laser is not the best choice to detect these molecules, these data may be useful in special cases, for example, when CO2 LIDAR is used to monitor the leakage of these gases from industrial areas.

Surely, the data in all our tables are only starting points in discussion about applicability of particular CO2-laser transitions for remote sensing under atmospheric conditions, because at many wavenumbers, the absorption by H2O may be much stronger than absorption by the gases of interest. Hence one always should find the tradeoff between the absorption of H2O and the absorption of these gases.

For example, the “best” line for NH3 detection by 26-laser in Table 4 is 10R(30) with (NH3) = 303 × 10−20 cm2. However, at this wavelength, the ratio (NH3)/(H2O) is only 4.4 × 105. If we choose another 26-laser line for NH3 detection, P(34) (931.0014 cm−1) with (NH3) = 55.2 × 10−20 cm2 and (H2O) = 0.0023 × 10−23 cm2, the ratio will be much higher: (NH3)/(H2O) = 2.4 × 107. Hence, this another 26-laser line is better for NH3 detection, although the value (NH3) is lower.

Therefore, we included H2O in our calculations; see the results in Tables 1, 2, and 3. Our (H2O) data in the tables should help to choose the “best” pairs of CO2-laser lines (absorbing and nonabsorbing) for remote sensing of the gases of interest. Note that the pair of CO2-laser wavenumbers may originate from two isotopically different CO2 lasers; therefore the possibility to use many isotopic variations of CO2 laser simplifies strongly the choice of such pairs.

4. Application to FIR Lasers

There are several important benchmark molecules which are normally used in CO2-laser-pumped FIR lasers: CH3OH, CH2F2, HCOOH, 15NH3, CD3OD, CD3 OH, CD3Cl, 13CD3I, and 13CH3F. The absorption of CO2 radiation by these molecules results in FIR-laser emission. Table 6 lists our values for CH3OH and HCOOH at low pressures, where the shapes of spectral lines of these molecules are given by Doppler effect. As one can see, there are a lot of interesting possibilities to obtain new strong sources of FIR radiation. One of them may be 9R(19) line of 268-laser, which has very large (HCOOH) value.


M Laser Line , cm−1 (M)a

CH3OH 26 10P(34) 1033.48800 126
36 10P(16) 1004.27987 67.2
28 10P(22) 1067.35888 93.0
38 10R(8) 1032.91023 200*
38 10R(40) 1050.77747 193*
38 10P(36) 998.62350 113
46 9R(46) 1010.98950 44.7*
46 9R(28) 1002.08279 19.4
48 9R(40) 1006.00000 146*
48 9R(24) 998.01156 107
268 10P(27) 1050.83825 368

HCOOH 26 10R(18) 1077.30252 186
26 10R(28) 1083.47878 189
26 10R(40) 1090.02837 976*
36 10R(28) 1037.16713 9.59
28 10P(8) 1078.04242 327
28 10R(34) 1104.91182 285
38 10R(44) 1052.63615 19.3
46 9R(26) 1000.94716 2.64
48 9R(30) 1001.17880 2.74
268 10R(19) 1086.22023 118

aAsterisk marks the cases where the (M) is large, but the CO2-laser line is marginal.

Although there is no direct relation between intensities of CO2 absorption and FIR emission, it is clear that using 1000 CO2-laser lines instead of 100–200 should increase strongly the amount of strong FIR-laser transitions.

5. Conclusion

The absorption cross sections and and parameters of some molecules (NH3, C2H4, CO2, O3, NO2, PH3, HNO3, SF6, CH3OH, HCOOH, OCS, CH3CN, C2H6, SO2, and H2O) at CO2 laser frequencies (12C16O2,13C16O2, 12C18O2, 14C16O2, 14C18O2, 13C18O2, and 12C16O18O) have been calculated with the use of spectroscopical parameters from GEISA database. The present results are in reasonable agreement with other experimental measurements for NH3, O3, and C2H4. The results of the calculations may be used in designing the differential absorption technique for remote monitoring of these molecules.

References

  1. C. Weitkamp, Lidar Range-Resolved Optical Remote Sencing of the Atmosphere, Springer Science and Business Media Inc., 2005.
  2. B. I. Vasil'ev and O. M. Mannoun, “IR differential-absorption lidars for ecological monitoring of the environment,” Quantum Electronics, vol. 36, no. 9, pp. 801–820, 2006. View at: Publisher Site | Google Scholar
  3. J. R. Quagliano, P. O. Stoutland, R. R. Petrin et al., “Quantitative chemical identification of four gases in remote infrared (9–11 μm) differential absorption lidar experiments,” Applied Optics, vol. 36, no. 9, pp. 1915–1927, 1997. View at: Google Scholar
  4. S. Lundqvist, C. O. Falt, U. Persson, B. Marthinsson, and S. T. Eng, “Air pollution monitoring with a Q-switched CO2-laser lidar using heterodyne detection,” Applied Optics, vol. 20, no. 14, pp. 2534–2538, 1981. View at: Google Scholar
  5. U. Persson, S. Lundqvist, B. Marthinsson, and S. T. Eng, “Computerautomated CO2-laser long-path absorption system for air quality monitoring in the working environment,” Applied Optics, vol. 23, no. 7, pp. 998–1002, 1984. View at: Google Scholar
  6. W. Schnell and G. Fischer, “Carbon dioxide laser absorption coefficients of various air pollutants,” Applied Optics, vol. 14, no. 9, pp. 2058–2059, 1975. View at: Google Scholar
  7. A. Mayer, J. Comera, H. Charpentier, and C. Jaussaud, “Absorption coefficients of various pollutant gases at CO2 laser wavelengths, application to the remote sensing of those pollutants: errata,” Applied Optics, vol. 17, no. 3, pp. 391–393, 1978. View at: Google Scholar
  8. A. Pal, C. D. Clark, M. Sigman, and D. K. Killinger, “Differential absorption lidar CO2 laser system for remote sensing of TATP related gases,” Applied Optics, vol. 48, no. 4, pp. B145–B150, 2009. View at: Publisher Site | Google Scholar
  9. K. I. Arshinov, M. K. Arshinov, V. V. Nevdakh, M.-Y. Perrin, A. Soufiani, and V. V. Yasnov, “Accuracy in determination of the temperature and partial pressure of CO2 in CO2:N2:H2O:NO2 mixtures by multiple-frequency laser probing,” Journal of Applied Spectroscopy, vol. 74, no. 6, pp. 903–909, 2007. View at: Publisher Site | Google Scholar
  10. M. Hamza, M. H. S. El-Ahl, and A. M. Hamza, “New laser system for sensitive remote sensing of ammonia in human breath,” in Proceedings of the Air Monitoring and Detection of Chemical and Biological Agents II, vol. 3855 of Proceedings of SPIE, pp. 28–33, September 1999. View at: Google Scholar
  11. L. Fiorani, F. Colao, and A. Palucci, “Measurement of Mount Etna plume by CO2-laser-based lidar,” Optics Letters, vol. 34, no. 6, pp. 800–802, 2009. View at: Publisher Site | Google Scholar
  12. L. Fiorani, F. Colao, A. Palucci, D. Poreh, A. Aiuppa, and G. Giudice, “First-time lidar measurement of water vapor flux in a volcanic plume,” Optics Communications, vol. 284, no. 5, pp. 1295–1298, 2011. View at: Publisher Site | Google Scholar
  13. P. P. Geiko and A. Tikhomirov, “Remote measurement of chemical warfare agents by differential absorption CO2 lidar,” Optical Memory and Neural Networks, vol. 20, no. 1, pp. 71–75, 2011. View at: Publisher Site | Google Scholar
  14. E. M. Telles, H. Odashima, L. R. Zink, and K. M. Evenson, “Optically pumped FIR laser lines from CH3OH: new laser lines, frequency measurements, and assignments,” Journal of Molecular Spectroscopy, vol. 195, no. 2, pp. 360–366, 1999. View at: Google Scholar
  15. C. Bellecci, M. Francucci, P. Gaudio et al., “Application of a CO2 dial system for infrared detection of forest fire and reduction of false alarm,” Applied Physics B, vol. 87, no. 2, pp. 373–378, 2007. View at: Publisher Site | Google Scholar
  16. P. Gaudio, M. Gelfusa, I. Lupelli et al., “First open field measurements with a portable CO2 lidar/dial system for early forest fires detection,” in Lidar Technologies, Techniques, and Measurements for Atmospheric Remote Sensing VII, September 2011. View at: Publisher Site | Google Scholar
  17. N. Jacquinet-Husson, L. Crepeau, R. Armante et al., “The 2009 edition of the GEISA spectroscopic database,” Journal of Quantitative Spectroscopy and Radiative Transfer, vol. 112, no. 15, pp. 2395–2445, 2011. View at: Publisher Site | Google Scholar
  18. L. F. Chernogor and A. S. Rashkevich, “Results of en-route monitoring of the laser gas polluting impurities in the atmosphere,” Eastern European Journal of Enterprise Technologies, vol. 52, article 57, 1987. View at: Google Scholar
  19. K. Fox, “Strengths of the SF6 transitions pumped by a CO2 laser,” Optics Communications, vol. 19, no. 3, pp. 397–400, 1976. View at: Google Scholar
  20. J. L. Lyman, R. G. Anderson, R. A. Fisher, and B. J. Feldman, “Absorption of pulsed CO2-laser radiation by SF6 at 140 K,” Optics Letters, vol. 3, no. 6, pp. 238–240, 1978. View at: Google Scholar
  21. H. Kariminezhad, P. Parvin, F. Borna, and A. Bavali, “SF6 leak detection of high-voltage installations using TEA-CO2 laser-based DIAL,” Optics and Lasers in Engineering, vol. 48, no. 4, pp. 491–499, 2010. View at: Publisher Site | Google Scholar
  22. U. Persson, B. Marthinsson, J. Johansson, and S. T. Eng, “Temperature and pressure dependence of NH3 and C2H4 absorption cross sections at CO2 laser wavelengths,” Applied Optics, vol. 19, no. 10, pp. 1711–1715, 1980. View at: Google Scholar
  23. J. N. Olsen, “Laser-initiated channels for ion transport: CO2-laser absorption and heating of NH3 and C2H4 gases,” Journal of Applied Physics, vol. 52, no. 5, pp. 3279–3285, 1981. View at: Publisher Site | Google Scholar
  24. R. R. Patty, G. M. Russwurm, W. A. McClenny, and D. R. Morgan, “CO2 laser absorption coefficients for determining ambient levels of O3, NH3, and C2H4,” Applied Optics, vol. 13, no. 12, pp. 2850–2854, 1974. View at: Google Scholar
  25. A. P. Force, D. K. Killinger, W. E. DeFeo, and N. Menyuk, “Laser remote sensing of atmospheric ammonia using a CO2 lidar system,” Applied Optics, vol. 24, no. 17, pp. 2837–2841, 1985. View at: Google Scholar
  26. Y. Zhao, “Line-pair selections for remote sensing of atmospheric ammonia by use of a coherent CO2 differential absorption lidar system,” Applied Optics, vol. 39, no. 6, pp. 997–1007, 2000. View at: Google Scholar
  27. B. D. Green and J. I. Steinfeld, “Absorption coefficients for fourteen gases at CO2-laser frequencies,” Applied Optics, vol. 15, p. 1688, 1975. View at: Google Scholar
  28. L. T. Molina and W. B. Grant, “FTIR-spectrometer-determined absorption coefficients of seven hydrazine fuel gases—implications for laser remote sensing,” Applied Optics, vol. 23, no. 21, pp. 3893–3900, 1983. View at: Google Scholar
  29. N. Menyuk, D. K. Killinger, and W. E. DeFeo, “Laser remote sensing of hydrazine, MMH, and UDMH using a differential-absorption CO2 lidar,” Applied Optics, vol. 21, no. 12, pp. 2275–2286, 1982. View at: Google Scholar
  30. J. S. Ryan, M. H. Hubert, and R. A. Crane, “Water vapor absorption at isotopic CO2 laser wavelengths,” Applied Optics, vol. 22, no. 5, pp. 711–717, 1983. View at: Google Scholar
  31. H. Ahlberg, S. Lundqvist, and S. T. Eng, “Absorption coefficients of chlorine-dioxide 12C1802 laser wavelengths: applications to remote monitoring in the working environment,” Applied Optics, vol. 23, no. 17, pp. 2902–2905, 1984. View at: Google Scholar
  32. F. Allario and R. K. Seals Jr., “Measurements of NH3 absorption coefficients with a 13C16O2 laser,” Applied Optics, vol. 14, no. 9, pp. 2229–2233, 1975. View at: Google Scholar
  33. Z. Zelinger, I. Jancik, and P. Engst, “Measurement of the NH3, CCl2F2, CHClF2, CFCl3, and CClF3 absorption coefficients at isotopic 13C16O2 laser wavelengths by photoacoustic spectroscopy,” Applied Optics, vol. 31, p. 6974, 1992. View at: Google Scholar
  34. D. Pereira, A. Scalabrin, G. P. Galvão, and K. M. Evenson, “13CD3OH and 12CD3OH optically pumped by a13CO2 laser: observations and assignments of FIR laser lines,” International Journal of Infrared and Millimeter Waves, vol. 13, no. 4, pp. 497–506, 1992. View at: Publisher Site | Google Scholar
  35. L. F. L. Costa, J. C. S. Moraes, F. C. Cruz, R. C. Viscovini, and D. Pereira, “Infrared and far-infrared spectroscopy of 13CH3OH: teraHertz laser lines and assignments,” Journal of Molecular Spectroscopy, vol. 241, no. 2, pp. 151–154, 2007. View at: Publisher Site | Google Scholar
  36. L. F. L. Costa, J. C. S. Moraes, F. C. Cruz, R. C. Viscovini, and D. Pereira, “CH3OH optically pumped by a 13CO2 laser: new laser lines and assignments,” Applied Physics B, vol. 86, no. 4, pp. 703–706, 2007. View at: Publisher Site | Google Scholar
  37. R. C. Viscovini, J. C. S. Moraes, L. F. L. Costa, F. C. Cruz, and D. Pereira, “DCOOD optically pumped by a 13CO2 laser: new terahertz laser lines,” Applied Physics B, vol. 91, no. 3-4, pp. 517–520, 2008. View at: Publisher Site | Google Scholar
  38. J. C. Petersen and G. Duxbury, “Observation and assignment of submillimetre laser lines from CH3OH pumped by isotopic CO2 lasers,” Applied Physics B, vol. 27, no. 1, pp. 19–25, 1982. View at: Publisher Site | Google Scholar
  39. J. C. Petersen and G. Duxbury, “Submillimetre laser lines from CH3OH pumped by a13C18O2 pump laser: observations and assignments,” Applied Physics B, vol. 34, no. 1, pp. 17–21, 1984. View at: Publisher Site | Google Scholar
  40. C. Freed, L. C. Bradley, and R. G. O'Donnell, “Absolute frequencies of lasing transitions in seven CO2 isotopic species,” IEEE Journal of Quantum Electronics, vol. 16, no. 11, pp. 1195–1206, 1980. View at: Google Scholar

Copyright © 2013 Asylkhan Rakhymzhan and Alexey Chichinin. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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