Vibrational Analysis of Tangled Spectra. II. Role of Phonon Side Band Structure in the T←S Spectra of Acetophenones

Abstract

Abstract T1,2←S0 phosphorescence excitation spectra of acetophenone, acetophenone-methyl-d3, and acetophenone-phenyl-d5 have been observed in the crystals at 4.2 K. Vibration analysis for the observed tangled spectra becomes possible only by the help of calculations which allow untangling of the tangled spectra. The calculations involve interstate mixings, by vibronic and environmental interactions, among 36 crude adiabatic Born-Oppenheimer vibronic functions of 3ππ* and 3nπ* states. A new aspect of the present work is introduction of a role of intermolecular phonon side bands into the calculations; this clearly showing that the observed spectra are reproduced much better than unless otherwise.