title: Communication: Vibrational and vibronic coherences in the two dimensional spectroscopy of coupled electron-nuclear motion.
abstract: We theoretically investigate the photon-echo spectroscopy of coupled electron-nuclear quantum dynamics. Two situations are treated. In the first case, the Born-Oppenheimer (adiabatic) approximation holds. It is then possible to interpret the two-dimensional (2D) spectra in terms of vibrational motion taking place in different electronic states. In particular, pure vibrational coherences which are related to oscillations in the time-dependent third-order polarization can be identified. This concept fails in the second case, where strong non-adiabatic coupling leads to the breakdown of the Born-Oppenheimer-approximation. Then, the 2D-spectra reveal a complicated vibronic structure and vibrational coherences cannot be disentangled from the electronic motion.
authors.affiliation: Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Emil-Fischer-Str. 42, Campus Nord, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Albert
authors.affiliation: Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Emil-Fischer-Str. 42, Campus Nord, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Falge
authors.affiliation: Departamento de Quimica Fisica, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Gomez
authors.affiliation: Departamento de Quimica Fisica, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Ignacio R
authors.initials: IR
authors.lastname: Sola
authors.affiliation: Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Emil-Fischer-Str. 42, Campus Nord, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Hildenbrand
authors.affiliation: Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Emil-Fischer-Str. 42, Campus Nord, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Engel