Effect of Charge-Transfer Interactions on the Radiative Rate Constant of ~1Δ_g Singlet

摘要

The radiative rate constant (k_r) and the lifetime of singlet oxygen were measured in 17 new solvents with low and high ionization potentials (IP) using an IR laser fluorimeter. Analysis of the values of k_r = 0.1 - 3.1 s~(-1) in 63 solvents shows that the charge-transfer interaction is the main factor in removal of the prohibition on the radiative spin-forbidden transition ~1Δ_g → ~3Σ_g~- in oxygen and leads to an increase in the k_r values in solvents with low ionization potentials. There is no correlation of k_r with the energy of dispersion interactions in collision complex O_2(~1Δ_g )…solvent. The averaged contribution of the dispersion interactions in the k_r dependence on the nature of solvent is estimated at 10%.