Simulation of a complex spectrum: Interplay of five electronic states and 21 vibrational degrees of freedom in C <inf>5</inf>H ⁺<inf>4</inf>

Abstract

Using a five-state, all-mode vibronic coupling model Hamiltonian derived in a previous publication [A. Markmann, J. Chem. Phys. 122, 144320 (2005)], we have calculated the photoelectron spectrum of the pentatetraene cation in the neighborhood of the B̃ E2 state, which can be represented with charge-localized components. To this end, quantum nuclear dynamics calculations were performed using the multiconfiguration time-dependent Hartree method, taking all 21 vibrational normal modes into account. Compared to experiment, the main features are reproduced but higher accuracy experiments are necessary to gauge the accuracy of the predictions for the vibronic progressions at the rising flank of the spectrum. © 2005 American Institute of Physics.