Luminescence of the (O2(a1Δg))2 collisional complex in the temperature range of 90-315 K: Experiment and theory

摘要: Experimental and theoretical studies of collision induced emission singlet oxygen molecules O2(a(1)Δg) in the visible range have been performed. The rate constants, half-widths, position peaks for bands (O2(a(1)Δg))2 collisional complex centered around 634 nm (2) 703 (3) measured temperature 90-315 K using a flow-tube apparatus that utilized gas-liquid chemical generator. absolute values spontaneous constants k2 k3 are found to be similar, with k3/k2 ratio monotonically decreasing from 1.1 at 300 0.96 90 K. slowly decreases but sharp increase its is below 100 experimental results were rationalized terms ab initio calculations ground excited potential energy transition dipole moment surfaces electronic states (O2)2 dimole, which compute within statistical model. best reproduced accuracy under 40% correctly described observed dependence. main contribution process (2), does not involve vibrational excitation O2 level, comes spin- symmetry-allowed 1(1)Ag←(1)B3u rectangular H configuration dimole. Alternatively, (3), one monomers becomes vibrationally state, predominantly due vibronically allowed 1(1)Ag←2(1)Ag by asymmetric O-O stretch vibration complex. strong vibronic coupling between nearly degenerate dimole makes intensities transitions comparable hence close another.