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

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 (<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.