Core-level spectroscopy and dynamics of free molecules

Abstract

A review of recent results on spectroscopy and dynamics of free molecules is presented. The experimental research reported here is mainly concerned with processes of core excitation and decay of isolated molecules, primarily investigated by resonant Auger spectroscopy. Several examples are shown concerning the interplay of the timescales of electron decay with nuclear motion involving dissociation processes, the occurrence of interference phenomena and recoil. The capability of such studies to reveal subtle details of the light-matter interaction, of the electronic structure and of the evolution of the short-lived states thus created is enlightened.

Molecular dynamics of NH3 induced by core-electron excitation

“…Excitation to a bound part of the N1s À1 4a 1 1 PES means that the molecule spends a longer time in the coreexcited state before Auger decay occurs. Three types of nuclear motion contribute to the photon energy dependent angular anisotropy observed for this pathway.…”

“…1,2 Nuclear motion in the core-excited state prior to electronic decay has been verified for a number of molecules [1][2][3][4][5][6][7] and has been observed to influence both electronic decay and fragmentation dynamics (and kinematics). 1,2 Nuclear motion in the core-excited state prior to electronic decay has been verified for a number of molecules [1][2][3][4][5][6][7] and has been observed to influence both electronic decay and fragmentation dynamics (and kinematics).…”

Signatures of attosecond electronic–nuclear dynamics in the one-photon ionization of molecular hydrogen: analytical model versusab initiocalculations

“…Moreover, the description is not limited to doubly excited electronic states embedded into the ionization continuum, but could in principle be applied to any transient state that decays by emitting an electron. For example, the resonant Auger decay, where nuclear motion in the core excited states has a strong influence on the final Auger electron spectra, can be a possible target of study (see [28,29] and the references therein).…”

Hidden double excitations in the oxygen inner-shell ionization continuum of CO

“…Core-level photoelectron spectroscopy experiments provide a deep insight into symmetry and photoionization dynamics, see, e.g., [1][2][3][4][5][6]. Especially important for core-level spectroscopy is resonant excitation, which provides a well-defined (in energy and symmetry) intermediate state [7,8]. While the most common experiments involve photoexcitation below a photoionization threshold, a wealth of resonant phenomena takes place also in the photoionization continuum.…”