Vibrational assignments for indole with the aid of ultrasharp phosphorescence spectra

Abstract

A site-selective study of the 3La phosphorescence from indole in solid argon at 20 K has revealed a special site from which the emission is exceptionally sharp (5 cm−1 fwhm). These spectra are compared with well-resolved (5 cm−1 fwhm) fluorescence from the 1Lb origin of indole under cold jet conditions. The results are compared with frequencies and Franck–Condon factors generated from ab initio electronic structure calculations on the ground and excited states. On the basis of the data and calculations, new assignments are made. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 72: 347–356, 1999