Electronic spectroscopy and dynamics of the low-lying <i>A</i> 3Σ+<i>u</i>, <i>C</i> 3Δ<i>u</i>, and <i>c</i> 1Σ−<i>u</i> states of O2 in van der Waals solids

Abstract

The 2900–2400 Å absorption of O2 in solid solutions is dominated by the C 3Δu←X 3Σ−g transition, unlike O2 in the gas phase. Isotopically resolved excitation spectra of v=0 C 3Δ1 emission in solid N2 host provide detailed vibrational and electronic C 3Δ spectroscopic parameters. The data establish absolute vibrational numbering for C 3Δ and c 1Σ, in the gas phase as well as in the solid. A progression of perturbations between v C 3Δ2 and v−2 A 3Σ+u is analyzed to show that this host induced interaction is characterized by a 27 cm−1 matrix element. Vibrational relaxation within both singlet and triplet excited states is ’’fast’’ in N2, Ar, and Xe hosts. It is experimentally proven that these spectra occur in isolated O2 monomers. Excited O2 photochemistry appears to occur in Xe host, but not in N2 host. A double resonance experiment of Rebane et al. is reinterpreted.