Knowledge Bank

Hydroxyl radicals produced by a microwave discharge of water vapor at high dilution in argon were deposited with a mixture of sulfur dioxide and argon onto a cesium Iodide window maintained al 12 K. The major products, formed on the surface of the condensing argon matrix, were the previously-re ported $HSO2$- anion, the HOSO radical, and the hydroxysulfonyl radical $HOSO2$. Five previously-unreported infrared absorptions of $HOSO2$ were observed, allowing assignment of all nine vibrational frequencies of this molecule, which is the precursor to acid rain Warming the matrix to allow diffusion caused significant growth of the hydroxysulfonyl radical absorptions; in addition, infrared bands due to sulfuric acid molecules appeared in the spectrum after diffusion, Oxygen-18 isotopic substitution data are reported for the first time for these two molecules.