Photon Energy Deposition in Strong-Field Single Ionization of Multielectron Molecules

Abstract

Molecules exposed to strong laser fields may coherently absorb multiple photons and deposit the energy into electrons and nuclei, triggering the succeeding dynamics as the primary stage of the light-molecule interaction. We experimentally explore the electron-nuclear sharing of the absorbed photon energy in above-threshold multiphoton single ionization of multielectron molecules. Using CO as a prototype, vibrational and orbital resolved electron-nuclear sharing of the photon energy is observed. Different from the simplest one- or two-electron systems, the participation of the multiple orbitals and the coupling of various electronic states in the strong-field ionization and dissociation processes alter the photon energy deposition dynamics of the multielectron molecule. The population of numerous vibrational states of the molecular cation as the energy reservoir in the ionization process plays an important role in photon energy sharing between the emitted electron and the nuclear fragments.

Strong Field Theories beyond Dipole Approximations in Nonrelativistic Regimes

“…Two kinds of processes are very fundamental in ultrafast laser-atom/molecule interactions, i.e., the deposition of photon energies into atoms and molecules, and the transfer of photon linear momentum into targets. Plenty of studies focused on the energy deposition and a series of intriguing ultrafast phenomena were explored, such as tunneling ionization [1], high harmonic generation and its synthesization of attosecond light pulses [2], nonsequential double ionization [3], coherent control of electron localization [4][5][6][7], energy sharing between electrons and nuclei [8]. For the second one, the transfer of photon linear momentum attracts much less attentions due to the fact that a photon is not an effective momentum carrier as compared to a nonrelativistic electron.…”

Orientation-dependent strong-field dissociative single ionization of CO

“…1(d) for the potential curves of CO + ]. The potential energy curves of the involved electronic states of CO + (calculation method is described in [7,21]), where the gray bar indicates the Franck-Condon ionization region of the ground state CO. The violet and orange arrows illustrate the transition pathways for the dissociation of CO + with molecular axis perpendicular and parallel to the UV field, respectively.…”

“…1(b), the angular distributions of the C + for the E H region (the outer ring) is broader than that for the E L region. It is because that the E L and E H regions are produced via different pathways [21,22]. The E H region is produced by removing one electron from HOMO-1 in the Frank-Condon region of CO, which populates the A 2 Π state of CO + and afterwards dissociates into C + and O via the D 2 Π state by absorbing two UV photons.…”

“…CO has been chosen as a prototype system for heteronuclear molecules of which the dynamics have been widely studied when interacting with strong laser fields [19][20][21][22]. It is known that the detailed electronic structures of molecules play decisive role in the strongfield-molecule interactions.…”

Photon-number-resolved asymmetric dissociative single ionization of H2

“…When exposed to a strong laser field, the electrons and nuclei of a molecule as a whole absorb multiple photons in the ionization and dissociation steps. As compared to the atoms, the electrons and nuclei of a molecule share the absorbed photon energy [36][37][38][39][40][41][42][43][44][45], i.e., the photon energy is correlatively partitioned between electrons and nuclei. Until now, the role of the photon energy sharing between the electron and nuclei on directional breaking of molecules has not been explicitly explored, in particular, the dependence on the total number of the photons absorbed by the molecule in the ionization and dissociation processes.…”