Laser-Induced Electron Transfer in the Dissociative Multiple Ionization of Argon Dimers

Abstract

We report on an experimental and theoretical study of the ionization-fragmentation dynamics of argon dimers in intense few-cycle laser pulses with a tagged carrier-envelope phase. We find that a field-driven electron transfer process from one argon atom across the system boundary to the other argon atom triggers subcycle electron-electron interaction dynamics in the neighboring atom. This attosecond electron-transfer process between distant entities and its implications manifests itself as a distinct phase-shift between the measured asymmetry of electron emission curves of the Ar þ þ Ar 2þ and Ar 2þ þ Ar 2þ fragmentation channels. This letter discloses a strong-field route to controlling the dynamics in molecular compounds through the excitation of electronic dynamics on a distant molecule by driving intermolecular electrontransfer processes.

Exploring photoelectron angular distributions emitted from molecular dimers by two delayed intense laser pulses

“…Furthermore, by applying methods based on angular streaking developed previously [9,13,14] and with the support from semiclassical trajectory simulations we are able to show that the dominant process underlying the rotation is scattering of the second-emitted electron on the neighboring molecular ion as it is driven away by the strong laser field. This finding adds to the emerging evidence for the key importance of laser-subcycle electron scattering dynamics in strong-field driven dimers [29] and clusters [33].…”

“…The orientation of the molecules/dimers was calculated from the fragment ions' momentum vectors p 1 = −p 2 . The reason for this selection was motivated by our recent work [29] in which we found that the ionization behavior of a dimer is strongly influenced by laser-driven electron scattering and transfer processes between the two entities of the dimer. To investigate the influence of such electron scattering processes with the double-pulse method, the dimer axis should be roughly aligned along the dominant ionization direction where the field strength is largest, i.e., the major axis of the polarization ellipse.…”

“…A widely used approach to study photoinduced intermolecular processes in femtosecond pump-probe experiments is to use small molecular van der Waals clusters and dimers as model systems [1,2]. In recent years, atomic and molecular dimers have also found increasing attention in experiments that study their ionization and fragmentation dynamics when driven by strong laser fields [16][17][18][19][20][21][22][23][24][25][26][27][28][29]. It was demonstrated that the analysis of the momenta of photoions or photoelectrons emitted during ionization fragmentation of dimers can provide detailed insight into, e.g., the ionization dynamics [30], the structural deformation induced by the strong-field interaction [26], the influence of a nearby charge on the dissociation behavior of molecules [27], or into laser-subcycle electron transfer processes [29].…”

“…In recent years, atomic and molecular dimers have also found increasing attention in experiments that study their ionization and fragmentation dynamics when driven by strong laser fields [16][17][18][19][20][21][22][23][24][25][26][27][28][29]. It was demonstrated that the analysis of the momenta of photoions or photoelectrons emitted during ionization fragmentation of dimers can provide detailed insight into, e.g., the ionization dynamics [30], the structural deformation induced by the strong-field interaction [26], the influence of a nearby charge on the dissociation behavior of molecules [27], or into laser-subcycle electron transfer processes [29]. A common finding of these studies is that during multiple ionization the nearby charge from the neighboring ion can have a decisive impact on the further ionization and/or fragmentation dynamics of the partner molecule.…”

Laser-subcycle control of electronic excitation across system boundaries

“…Recently, using the argon dimer Ar 2 as a model system for two closely-spaced but separate quantum entities, we demonstrated for the first time CEP-control over electron transfer reactions across system boundaries [23]. We showed that an electron emitted from one argon atom and driven to the other atom by the strong laser field, can become transiently captured before it leaves toward the detector.…”