Chemistry in Solid Parahydrogen at Low Temperature

Cryogenic solid molecular hydrogen provides a weakly perturbing crystal environment to study the low temperature (2-5 K) chemistry of embedded reactive species. Solid hydrogen is considered a quantum solid since the zero-point translational motion of the light hydrogen molecules dominates the physical properties of the crystal. Photodissociation of molecules embedded in the solid hydrogen provide a means of generating molecular species \textit{in situ} that normally would react with H$_{2}$ at room temperature, but at the low temperatures at which hydrogen is a solid these species can be trapped and studied spectroscopically. Recent studies of the photodissociation of Cl$_{2}$ in solid parahydrogen (hydrogen crystals enriched in the para-H$_{2}$ nuclear spin isomer) reveal a means to study the infrared-induced Cl + H$_{2}$(v=1) $\to $ HCl + H reaction at temperatures below 2 K. Current efforts are aimed at studying the analogous O + H$_{2}$(v=1) $\to $ OH + H reaction and the most recent results and analysis will be presented at the meeting.