Internuclear-distance dependence of electron correlation in nonsequential double ionization of H_2

Abstract

Using three-dimensional classical ensembles, we have investigated the internuclear distance dependence of nonsequential double ionization (NSDI) of H(2) molecules by an 800 nm, 1x10(14) W/cm(2) laser pulse. For the internuclear distance R ranging from 2 to 12 a.u., the NSDI of H(2) provides rich correlation patterns in the two-electron momentum distributions. These correlation patterns essentially reveal different microscopic dynamics in NSDI process. Moreover, our calculations show that R approximately 4 a.u. is the critical distance for double ionization yield of H(2). These results are qualitatively explained based on the classical barrier expression model and back analysis.

H2: the benchmark molecule for ultrafast science and technologies

“…By selecting only those high energy protons, Alnaser et al were also able to reproduce the archetypical kneestructure in the double ion yield [85]. Modeling the combined electron-nuclear dynamics in H 2 with quantum [87][88][89] and classical models [90] allowed a detailed analysis of the NSDI mechanisms such as multiple recollisions, and recollision induced excitation. Furthermore, theory specifically addressed NSDI in few-cycle optical pulses [91,92], the alignment dependence of NSDI [93][94][95] and its wavelength dependence [96].…”

Intensity dependence of nonsequential double ionization of aligned asymmetric molecules

“…The 3D classical ensemble model is introduced in [14] and widely recognized as a useful approach in studying high-field double ionization of atoms [35,36] and molecules [29,31,32]. It is similar to the semiclassical rescattering model [37], where the ionization of the first electron from the bound state to the continuous state is treated by the tunneling ionization theory and the subsequent evolution of the ionized electron and the bound electron in the combined Coulomb potential and the laser fields is described by a classical Newtonian equation.…”

“…Compared with atoms, NSDI of molecules have more factors to be considered, such as the orbital symmetry [26,27], the internuclear distance [28,29] and molecular alignment with respect to the laser polarization [30,31]. The experimental and theoretical studies for symmetric diatomic molecules by multi-cycle laser pulses have indicated that the two electrons involved in NSDI more likely escape into the opposite hemispheres for the perpendicular alignment than for the parallel alignment [30,31].…”

Electron dynamics of molecular double ionization by elliptically polarized few-cycle laser pulses

“…Typically, DI distinguishes between sequential double ionization (SDI) [1][2][3][4] and non-sequential double ionization (NSDI) [5][6][7][8][9][10]. In SDI the electrons are assumed to tunnel-ionize independently while in NSDI the strong electron correlation are existed.…”