PHOTODYNAMICS IN OXYGEN DOPED SOLID DEUTERIUM

A spectroscopic investigation of O-2 isolated in D-2 matrices is reported. Standard matrix isolation methods lead to only a small observable concentration of isolated molecules in D-2 and fail in the case of H-2. Both resonant excitation of the molecule over the A'((3) Delta(u))<--X((3) Sigma(g)(-)) transition, and g dissociative pumping at 193 nm, lead to vibrationally relaxed A'-->X emission, with a lifetime of 5.4 mu s. Independent of the initial Omega component accessed, the fluorescence is polarized with a polarization ratio of 1.25+/-0.05; indicating that O-2 does not rotate and that the transition gains its intensity by crystal held induced mixing between the (3) Delta(u) and a nearby (3) Pi(u) state. This uniquely identifies the anisotropy of the local field as Y-43 + Y-4-3, which in turn implies that the molecule is trapped in an fee site with its axis aligned along the [111] direction. The observed zero phonon line intensities can be explained consistently if the spin-orbit multiplet is assumed to be normal, in contrast with the accepted scheme in the gas phase. The zero phonon lines of O-2 isolated in D-2, show librational satellites with a 15 cm(-1) spacing in the A' state, and similar to 25 cm(-1) spacing in the X state. intensity analysis of these progressions leads to the conclusion that the molecular axis in the excited state is lilted relative to the ground state. Deposits in D-2 and H-2 samples overcoated with Xe, after annealing, exhibited spectra of isolated O-2 which an perturbed by the Xe film. (C) 1995 American Institute of Physics.