Quantum yield and rate constant of the singlet 1Δg oxygen luminescence in an aqueous medium in the presence of nanoscale inhomogeneities

Abstract

The quantum yields and lifetimes of photosensitized luminescence of the ¹Δ_g state of singlet oxygen in an aquatic media with a controlled concentration of dielectric anisotropy centers (polyethylene glycol) have been measured using the methods of laser fluorometry. It is established that the quantum yield and the rate constant (k_r) of the a¹Δ_g → X³Σ_g^- luminescence of ¹O₂ increase as the polymer concentration increases. The effect is analyzed within a general approach involving a relationship between kr and dielectric properties of the medium and is explained by the increased density of photon states and the local field factor in the space around O₂(а¹Δ_g).