title: The photoisomerization mechanism of azobenzene: a semiclassical simulation of nonadiabatic dynamics.
abstract: We have simulated the photoisomerization dynamics of azobenzene, taking into account internal conversion and geometrical relaxation processes, by means of a semiclassical surface hopping approach. Both n-->pi* and pi-->pi* excitations and both cis-->trans and trans-->cis conversions have been considered. We show that in all cases the torsion around the N==N double bond is the preferred mechanism. The quantum yields measured are correctly reproduced and the observed differences are explained as a result of the competition between the inertia of the torsional motion and the premature deactivation of the excited state. Recent time-resolved spectroscopic experiments are interpreted in the light of the simulated dynamics.
authors.affiliation: Dipartimento di Chimica e Chimica Industriale, Università di Pisa, v. Risorgimento 35, 56126 Pisa, Italy.
authors.forename: Cosimo
authors.initials: C
authors.lastname: Ciminelli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Granucci
authors.forename: Maurizio
authors.initials: M
authors.lastname: Persico