INFRA-RED SPECTRA AND GEOMETRY OF SO2 AND SEO2 IN RARE GAS MATRICES

Infra-red spectra have been obtained for SO2 and SeO2, matrix isolated in solid neon and argon, from which the fundamental frequencies ν1, ν2and ν3 were determined. Isotope shift measurements indicated bond angles for SO2 of 117° ± 1° and for SeO2 of 110° ± 2°, which differ very slightly from reported gas phase values. New dimeric species of SO2 and SeO2 were also identified in the i.r. spectra. The (SO2)2 species was formed by controlled diffusion of monomers in the rare gas solid while (SeO2)2 was a component of the equilibrium vapor over molten SeO2. Prior to matrix isolation, the SO2 was heated in a nickel Knudsen cell at temperatures ranging from 25 to 1000°C. No new i.r.-active species were formed, indicating the postulated structural isomer of SO2 to be unstable or of very low concentration under Knudsen cell conditions. © 1969.