ELECTRONIC SPECTROSCOPY AND DYNAMICS OF THE LOW LYING $A^{3}{\Sigma_{u}}^{+}, C^{3}\Delta_{u}$ , AND $C^{1}{\Sigma_{u}}^{-}$ STATES OF $O_{2}$ IN VAN DER WAALS' SOLID HOSTS

Abstract

The 2800-2400 {\AA} absorption of $O_{2}$ in solid solutions is dominated by the $C^{3}\Delta_{u}\leftrightarrow ^{3}{\Sigma_{g}}^{-}$ transition, unlike $O_{2}$ in the gas phase, Isotopically resolved excitation spectra of v^{\prime}=O $C^{3}\Delta_{1}$ emission in solid $N_{2}$ host provide detailed vibrational and electronic $C^{3}\Delta$ spectroscopic parameters. The data establish absolute vibrational numbering for $c^{3}\Delta$ and $c^{1}\Sigma$, in the gas phase as well as in the solid. A progression of perturbations between v^{\prime} $C^{3}\bigtriangleup_{2}$ and $v^{\prime}-2 A^{3}\Sigma_{u}+$ is analyzed to show that this host-Induced, symmetry-forbidden interaction is characterized by a matrix element H = 27 $cm^{-1}$. Vibrational relaxation within both singlet and triplet excited states is ``fast” in $N_{2}$, Ar, and Xe hosts. It is experimentally proven that these spectra occur in isolated $O_{2}$ monomers. Excited $O_{2}$ photo-chemistry appears to occur in Xe host, but not in $N_{2}$ host.