Multielectron Effects in Charge Asymmetric Molecules Induced by Asymmetric Laser Fields

Abstract

Using a 45 fs pump pulse at 800 nm, a wave packet is created in a charge asymmetric dissociation channel of iodine, I(2)(2+)→I(2+)+I(0+) (2,0). As the molecule dissociates, a two-color (1ω2ω) probe pulse is used to study the dynamics as a function of internuclear separation R. We find a critical region of R in which there is spatially asymmetric enhanced ionization of the (2,0) channel to a counterintuitive (1,2) channel. In this region the I(0+) is ionized such that one electron is released to the continuum and another is transferred to the I(2+) resulting in I(0+)→I(2+) and I(2+)→I(1+). At larger R, the ionization is consistent with simple one-electron ionization in a double well where I(0+)→I(1+). We find qualitative agreement between simulations and experiment further highlighting the importance of multielectron effects in the strong-field ionization of molecules.

Multielectron effects in strong-field dissociative ionization of molecules

“…Those measurements are consistent with the notion that the charge-transfer depletion mechanism observed in the enhanced ionization of I 2 2+ [15] also dominates the production of N 2 (2,1). Interestingly, a different phase dependence for the directional emission of N 2+ from the N 2 (2,1) and N 2 (2,0) channels, not explained by the chargeexchange mechanism, was observed in another two-color experiment [16].…”

“…Two-color pump-probe measurements in N 2 , analogous to those used to study strong-field dissociative ionization of I 2 [15], might provide additional information on which ionization mechanisms dominate under different experimental conditions. However, such experiments would be extremely difficult for light molecules such as N 2 , due to the short time (ß25 fs) required for the dissociating molecular ion to expand to R c [17].…”

“…To achieve the best momentum resolution, the z axis is oriented along the time-of-flight direction of the spectrometer, while the supersonic molecular jet propagates along the y axis. Since the charge-transfer effect [15] and electron-localization-assisted enhanced ionization are only active for molecules aligned along the ionizing field [6,7,9,10], we restrict our data analysis and discussion to ions ejected within a 45°cone centered on the major polarization (i.e., y) axis.…”

“…In recent pump-probe experiments, Tagliamonti et al [15] showed that, depending on the internuclear distance, intramolecular electron redistribution can play an important role in multielectron dissociative ionization. Specifically, they considered the creation of the triply ionized dissociation channel, I…”

Field-assisted doublon manipulation in the Hubbard model: A quantum doublon ratchet

“…By contrast, the rectification effect in our protocol relies on the interaction between the two particles that form the doublon, which will also allow us to use the protocol for a controlled transmutation of more complex states. Moreover, the mechanism can be viewed as a generalization of an optimal control problem which has been discussed for a double quantum dot system [21] and is in line with charge transfer effects in molecules which are exposed to asymmetric laser fields [22]. …”