Solvatochromic shift of the 0-0 phosphorescence band and change of polarizability in the a1δg → X 3∑g - -transition in the oxygen molecule

We used known experimental data to analyze the influence of intermolecular interactions on the position of the 0-0-band a1Δg → X3∑ g - phosphorescence of molecular oxygen in solutions. A bathochromic (red) shift caused by dispersion interactions and fluctuations of the internal electric field (induction effect) is analyzed employing new formulas obtained by us in the framework of the Onsager model. The contributions from intermolecular repulsion and higher multipole interactions to the shift of the spectrum are also discussed. It is found that the polarizability in the a1Δg state is higher than in the X3∑ g t- state by 0.19 ± 0.03 Å3. Taking into account the induced nature of O2 phosphorescence in solutions, it is noted that the change of polarizability Δαeg = 0.19 Å3 should differ from the change of Δαeg inherent in free molecular oxygen. © 2007 Springer Science+Business Media, Inc.