Ab initio calculations of vibronic spectra for indole

Detailed vibronic fluorescence spectra from the 1Lb and 1La state origins of indole are computed from the geometry differences and ground state normal modes determined by GAUSSIAN 92 and a program to calculate Franck-Condon factors. The combination of using CIS/3-21G and HF/3-21G basis sets for excited and ground state geometries and MP2/6-31G∗ for the ground state vibrational modes captures many subtle details seen in the experimental 1Lb fluorescence.