Excited state structure of isolated 4-cyanoindole from a combined Franck-Condon and rotational constants analysis†

Abstract

Abstract The changes of the structure of 4-cyanoindole upon electronic excitation have been determined from a combined Franck-Condon and rotational constants fit. The geometry changes were fit to simultaneously reproduce the intensities of 72 lines in the fluorescence emission spectra, obtained via excitation of six different vibronic bands in the first excited singlet state, along with the three rotational constants from rotationally resolved electronic spectra.