Strong-field double ionization dynamics of vibrating HeH⁺ versus HeT⁺

Abstract

We study double ionization (DI) dynamics of vibrating HeH+ versus its isotopic variant HeT+ in strong laser fields numerically. Our simulations show that for both cases, these two electrons in DI prefer to release together along the H(T) side. At the same time, however, the single ionization (SI) is preferred when the first electron escapes along the He side. This potential mechanism is attributed to the interplay of the rescattering of the first electron and the Coulomb induced large ionization time lag. On the other hand, the nuclear motion increases the contributions of these two electrons releasing together along the He side. This effect differentiates DI of HeH+ from HeT+.

Coulomb Effects on time-trajectory-resolved high-order harmonic generation

“…The existence of the Coulomb-induced ionization time lag △t suggests the use of a four-step model (pink curve), including tunneling, lag, propagation and recombination to describe the HHG. This lag discussed above has a profound influence on dynamics of the electron after tunneling in the strong laser field [37,38]. As discussed in [22] for 2D cases, this lag gives rise to the tunneling-out and emission times of HHG for both long and short electron trajectories dozens of attoseconds earlier than the predictions of SFA.…”

Local most-probable routes and classic-quantum correspondence in strong-field two-dimensional tunneling ionization

“…It should be stressed that in this paper, we focus our discussions on atoms. For molecules with multi-center structure, some complex effects emerge in strong-field ionization, such as quantum interference between the molecular centers during tunneling [53][54][55], permanent dipole induced large Stark effect [56][57][58], laser induced nuclear quick stretching [59][60][61][62][63], and permanent dipole induced direct vibration excitation [64][65][66], etc.. For the purpose of achieving more precise control and measurement of the electron motion within the molecule with 2D laser fields, studies on influences of molecular structure and structure-related effects on properties of 2D tunneling are also expected.…”

Characterizing Sub-Cycle Electron Dynamics of Polar Molecules by Asymmetry in Photoelectron Momentum Distributions

“…On average, the value of this lag can be taken as the time difference between the maximum of the electric field and the instant around which the ionization increases remarkably, as the horizontal arrows show. This lag has important influences on strong-field dynamics of the tunneling electron [9,18,32]. The lag phenomenon is not noticeable for the second half laser cycle.…”