Title: Infrared absorption of CH(3)SO(2) observed upon irradiation of a p-H(2) matrix containing CH(3)I and SO(2)
Authors: Lee, Yu-Fang
Lee, Yuan-Pern
Department of Applied Chemistry
Institute of Molecular science
Issue Date: 28-Mar-2011
Abstract: Irradiation with a mercury lamp at 254 nm of a p-H(2) matrix containing CH(3)I and SO(2) at 3.3 K, followed by annealing of the matrix, produced prominent features at 633.8, 917.5, 1071.1 (1072.2), 1272.5 (1273.0, 1273.6), and 1416.0 cm(-1), attributable to nu(11) (C-S stretching), nu(10) (CH(3) wagging), nu(8) (SO(2) symmetric stretching), nu(7) (SO(2) antisymmetric stretching), and nu(4) (CH(2) scissoring) modes of methylsulfonyl radical (CH(3)SO(2)), respectively; lines listed in parentheses are weaker lines likely associated with species in a different matrix environment. Further irradiation at 365 nm diminishes these features and produced SO(2) and CH(3). Additional features at 1150.1 and 1353.1 (1352.7) cm(-1) are tentatively assigned to the SO(2) symmetric and antisymmetric stretching modes of ISO(2). These assignments are based on comparison of observed vibrational wavenumbers and (18)O- and (34)S-isotopic shifts with those predicted with the B3P86 method. Our results agree with the previous report of transient IR absorption bands of gaseous CH(3)SO(2) at 1280 and 1076 cm(-1). These results demonstrate that the cage effect of solid p-H(2) is diminished so that CH(3) radicals, produced via UV photodissociation of CH(3)I in situ, might react with SO(2) to form CH(3)SO(2) during irradiation and upon annealing. Observation of CH(3)SO(2) but not CH(3)OSO is consistent with the theoretical predictions that only the former reactions proceed via a barrierless path. (C) 2011 American Institute of Physics. [doi:10.1063/1.3567117]
URI: http://dx.doi.org/10.1063/1.3567117
ISSN: 0021-9606
DOI: 10.1063/1.3567117
Volume: 134
Issue: 12
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