Vibrational and Electronic Excitation of Molecules by Short-Pulse Strong Laser Fields

Abstract

For weak electromagnetic fields, vibrational and electronic excitation of molecules generally occurs through resonant one-photon interactions or two-photon Raman-type transitions. Short-pulse strong laser fields open up a variety of new excitation schemes, which are characterized by non-resonant or high-order resonant interactions. The study of vibrational and electronic excitation of molecules by strong laser fields is important for a number of reasons: (1) It reveals new features of the strong field interaction with molecules, such as R-dependent ionization and inner orbital ionization; (2) It informs other studies such as high-harmonic generation and quantum tomography. In particular, it probes various assumptions that are made, such as only one orbital is active and the ionization rate is a maximum along the internuclear axis; (3) It allows for the spectroscopy of previously inaccessible states of the molecules, such as the charge resonant state of I22+ and the excited states of H2+; (4) It may lead to novel methods for creating population inversions in the vaccum-ultraviolet; (5) It may lead to new methods for coherent control of thermal ensembles. In this paper, we present an overview of these strong field excitation schemes and give examples for many of them. © 2010 Springer-Verlag Berlin Heidelberg.