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

Abstract

The 2900–2400 Å absorption of O₂ in solid solutions is dominated by the C ³Δ_u←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.