Raman spectra and cross sections of ammonia, chlorine, hydrogen sulfide, phosgene, and sulfur dioxide toxic gases in the fingerprint region 400-1400 cm−1

R L Aggarwal,L W Farrar,T H Jeys,S Di Cecca

doi:10.1063/1.4942109

Abstract

Raman spectra of ammonia (NH3), chlorine (Cl2), hydrogen sulfide (H2S), phosgene (COCl2), and sulfur dioxide (SO2) toxic gases have been measured in the fingerprint region 400-1400 cm−1. A relatively compact (&lt;2′x2′x2′), sensitive, 532 nm 10 W CW Raman system with double-pass laser and double-sided collection was used for these measurements. Two Raman modes are observed at 934 and 967 cm−1 in NH3. Three Raman modes are observed in Cl2 at 554, 547, and 539 cm−1, which are due to the 35/35 35/37, and 37/37 Cl isotopes, respectively. Raman modes are observed at 870, 570, and 1151 cm−1 in H2S, COCl2, and SO2, respectively. Values of 3.68 ± 0.26x10−32 cm2/sr (3.68 ± 0.26x10−36 m2/sr), 1.37 ± 0.10x10−30 cm2/sr (1.37 ± 0.10x10−34 m2/sr), 3.25 ± 0.23x10−31 cm2/sr (3.25 ± 0.23x10−35 m2/sr), 1.63 ± 0.14x10−30 cm2/sr (1.63 ± 0.14x10−34 m2/sr), and 3.08 ± 0.22x10−30 cm2/sr (and 3.08 ± 0.22x10−34 m2/sr) were determined for the differential Raman cross section of the 967 cm−1 mode of NH3, sum of the 554, 547, and 539 cm−1 modes of Cl2, 870 cm−1 mode of H2S, 570 cm−1 mode of COCl2, and 1151 cm-1 mode of SO2, respectively, using the differential Raman cross section of 3.56 ± 0.14x10−31 cm2/sr (3.56 ± 0.14x10−35 m2/sr) for the 1285 cm−1 mode of CO2 as the reference.

Highlights

The Raman spectra and cross sections of toxic gases are important for the detection of these gases using Raman spectroscopy in the fingerprint region 400-1400 cm−1
We report the measurement of the Raman spectra and cross sections of ammonia (NH3), chlorine (Cl2), hydrogen sulfide (H2S), phosgene (CCl2O), and sulfur dioxide (SO2) toxic gases in the fingerprint region 400-1400 cm−1 using the Raman cross section of the 1285 cm−1 mode of carbon dioxide (CO2) as the reference.[9]
Raman cross sections of NH3, Cl2, H2S, and CClO2 have been measured for the first time in the fingerprint region

Summary

INTRODUCTION

The Raman spectra and cross sections of toxic gases are important for the detection of these gases using Raman spectroscopy in the fingerprint region 400-1400 cm−1. Raman spectra and cross sections are important for homeland security and other applications.[1,2] Raman cross sections of a number of gases (CH4, C2H6, C3H8, C6H6, CO, CO2, F2, HBr, HCl, HF, H2, H2O, H2S, N2, NH3, ND3, NO, N2O, O2, O3, and SO2) have been reported previously.[3,4,5,6,7,8] In this paper, we report the measurement of the Raman spectra and cross sections of ammonia (NH3), chlorine (Cl2), hydrogen sulfide (H2S), phosgene (CCl2O), and sulfur dioxide (SO2) toxic gases in the fingerprint region 400-1400 cm−1 using the Raman cross section of the 1285 cm−1 mode of carbon dioxide (CO2) as the reference.[9] Raman cross sections of NH3, Cl2, H2S, and CClO2 have been measured for the first time in the fingerprint region. Our value of the Raman cross section of SO2 is 1.5x larger than that reported previously.[3,4]

EXPERIMENTAL

RESULTS AND DISCUSSION

SUMMARY