Fourier Transform Microwave and Millimeter-Wave Spectroscopy of Bromoiodomethane, CH sub(2)BrI

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 118; no. 50; pp. 11744 - 11750
• Main Authors: Bailleux, S, Duflot, D, Taniguchi, K, Sakai, S, Ozeki, H, Okabayashi, T, Bailey, W C
• Format: Journal Article
• Language: English
• Published: 18-12-2014
• Subjects: Constants; Fourier transforms; Microwaves; Molecular structure; Monitors; Rotational spectra; Spectroscopy
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp510119e

Bromoiodomethane, CH sub(2)BrI, is a molecule of natural origin emitted in significant amount into the marine boundary layer. It can easily be decomposed by solar radiation, releasing Br and I atoms in the troposphere, which in turn impacts the atmospheric chemistry. Spectroscopy is an invaluable tool to monitor species present in the atmosphere. Since no high-resolution spectroscopic studies are available for this dihalomethane, we have investigated the rotational spectra of the two bromine isotopologues of CH sub(2)BrI in its vibrational ground state in the microwave and millimeter-wave regions. Transitions of b-type have been recorded by Fourier transform microwave spectroscopy below 25 GHz while both a- and b-type spectral lines have been measured below 230 GHz. Observed transitions correspond to energy levels with J less than or equal to 132 and Ka less than or equal to 14. Molecular constants including those describing the nuclear quadrupole coupling tensors for super(79)Br, super(81)Br, and super(127)I were accurately determined from the least-squares analysis of a total of 1873 distinct transition frequencies (of which 943 belong to the CH sub(2) super(79)BrI isotopologue). An experimental (r sub(0)) structure of the title species has been derived from the two sets of rotational constants.