Imaging the Temporal Evolution of Molecular Orbitals during Ultrafast Dissociation

Abstract

We investigate the temporal evolution of molecular frame angular distributions of Auger electrons emitted during ultrafast dissociation of HCl following a resonant single-photon excitation. The electron emission pattern changes its shape from that of a molecular σ orbital to that of an atomic p state as the system evolves from a molecule into two separated atoms.

Role of ultrafast dissociation in the fragmentation of chlorinated methanes

“…This enabled us to do measurements which so-far have been impractical due to the time limitations of a typical synchrotron beamtime. For example, a particular coincidence ion can be monitored as a function of incident photon energy, as was demonstrated by Kokkonen et al 17 Similar measurement scheme was later utilized by Sann et al where they performed a photon energy scanned coincidence measurements while also measuring other parameters, such as the electron emission angle dependency 47 .…”

Photophysics of indole upon X-ray absorption

“…The connection between the RF and the MF requires unique molecular fragments, e. g., "marker atoms", and prior knowledge about the directionality of the fragmentation to determine the orientation of the molecule within the RF. Studies in the RF include recoil-frame angle-resolved photoelectron spectra (RF-ARPES), [29,[34][35][36][37][38] which allow to image molecular orbitals and their temporal evolution during dissociation, [37] or to extract structure and molecular dynamics information by "diffraction from within" [39] type of experiments. For such experiments, it is highly advantageous to locally ionize the molecule at a specific atom, which can be achieved by innershell ionization via extreme ultraviolet radiation, soft x-ray, or x-ray radiation.…”

“…For such experiments, it is highly advantageous to locally ionize the molecule at a specific atom, which can be achieved by innershell ionization via extreme ultraviolet radiation, soft x-ray, or x-ray radiation. Localized ionization provides also access to the local electronic structure and excited state dynamics, [37,40,41] and can be used to break specific bonds. [42] Here, isolated indole (C 8 H 7 N) molecules were ionized by a single (soft) x-ray photon with an energy of 420 eV, i. e., ∼10 eV above the nitrogen 1s ionization threshold, the N(1s) edge.…”

Fullerene Dynamics with X-Ray Free-Electron Lasers

“…The initial charge is induced with high degrees of temporal and spatial localization, thus making the data analysis easier to handle. The new FEL family of ultrafast xuv/X-ray complement and extend the work carried out by tabletop lasers [36], xuv [37], synchrotron [38], or photon sources.…”