Anharmonic V–V pumping and asymmetric electron-elementary excitation interaction in emission and absorption of O2(Δg) in the crystalline phases of oxygen

Three luminescence bands in the yellow and red spectral region, which are related to the ¹Δ_g¹Δ_g→³Σ_g^{? 3}Σ_g^? double electronic transition of O₂, have been investigated in the , β, and γ phase of solid oxygen. The temperature dependence of the intensity of the yellow band is strongly influenced by emission from higher vibrational levels of O₂(¹Δ_g), which are populated by anharmonic V–V pumping. The broken mirror symmetry of the luminescence and absorption bands in the phase of solid O₂ points to an interaction between the electrons and the elementary excitations of the crystal, which is different in the ground and excited electronic states, e.g., a quadratic electron–phonon interaction.