Photoionization of Benzophenone in the Gas Phase: Theory and Experiment.

We report on the single photoionization of jet-cooled benzophenone using a tunable source of VUV synchrotron radiation coupled with a photoion/photoelectron coincidence acquisition device. The assignment and the interpretation of the spectra are based on a characterization by ab initio and density functional theory calculations of the geometry and of the electronic states of the cation. The absence of structures in the slow photoelectron spectrum is explained by a congestion of the spectrum due to the dense vibrational progressions of the very low frequency torsional mode in the cation either in pure form or in combination bands.

Gas phase dynamics of triplet formation in benzophenone.

Benzophenone is a prototype molecule for photochemistry in the triplet state through its high triplet yield and reactivity. We have investigated its dynamics of triplet formation under the isolated gas phase conditions via femtosecond and nanosecond time resolved photoelectron spectroscopy. This represents the complete evolution from the excitation in S2 to the final decay of T1 to the ground state S0.

Surface hopping trajectory simulations with spin-orbit and dynamical couplings.

In this paper we consider the inclusion of the spin-orbit interaction in surface hopping molecular dynamics simulations to take into account spin forbidden transitions. Two alternative approaches are examined. The spin-diabatic one makes use of eigenstates of the spin-free electronic Hamiltonian and of Ŝ(2) and is commonly applied when the spin-orbit coupling is weak.

Oscillator strength and polarization of the forbidden n-->pi* band of trans-azobenzene: a computational study.

The trans-azobenzene molecule is thought to prefer a planar C2h geometry, in gas phase as well as in solution, according to the most recent computational studies. As a consequence, the weak n-->pi* absorption band is forbidden by symmetry at the equilibrium geometry, and its intensity depends on the effect of the vibrational motions on the electronic structure. In this computational study, we determine the contribution of the vibrational modes to the oscillator strength, taking into account the anharmonicity, the thermal distributions, and the solvent effects.