First principle simulation of vibrationally resolved electronic transition of phenyl radical

The A 2 B 1 ← X ˜ 2 A 1 electronic transition of phenyl radical has been studied by a recently introduced procedure to compute vibrationally resolved electronic spectra from first principles. Structural and vibrational properties have been obtained with the B3LYP/TD-B3LYP//N07D model, designed for computational studies of free radicals. The Franck–Condon Herzberg–Teller (FC-HT) spectra computed taking into account changes in structures, normal modes, and vibrational frequencies between both electronic states closely resemble their experimental counterpart. It is shown that full-dimensional vibronic models are necessary to reproduce correctly the spectrum shape and should be fully exploited prior to analyze the possible role of nonadiabatic effects.