Dynamic Core Polarization in Strong-Field Ionization of CO Molecules

Abstract

The orientation-dependent strong-field ionization of CO molecules is investigated using the fully propagated three-dimensional time-dependent Hartree-Fock theory. The full ionization results are in good agreement with recent experiments. The comparisons between the full method and the single active orbital method show that although the core electrons are generally more tightly bound and contribute little to the total ionization yields, their dynamics cannot be ignored, which effectively modifies the behavior of electrons in the highest occupied molecular orbital. By incorporating it into the single active orbital method, we identify that the dynamic core polarization plays an important role in the strong-field tunneling ionization of CO molecules, which is helpful for the future development of the tunneling ionization theory of molecules beyond the single active electron approximation.

Influence of permanent dipole and dynamic core-electron polarization on tunneling ionization of polar molecules

“…Following Ref. [33] we also take into account the interaction of the active electron with the dynamic polarization of core electrons induced by the laser. This potential is written as…”

“…[36,37]. To avoid the singularity at r = 0 we follow Zhang et al [33] and apply a cutoff for V p in Eq. (4) at certain r c .…”

“…This choice of short pulses is made for easy comparison with the earlier calculations in Refs. [33,43].…”

“…Quite recently, Zhang et al [33] showed that experimental data for CO in Refs. [23,25] can be nicely reproduced if the dynamic polarization of the core electrons is taken into account.…”

Analytical model for calibrating laser intensity in strong-field-ionization experiments

“…Accurate calculations of ionization probability for a fixed laser intensity can be accomplished by solving the timedependent Schrödinger equation (TDSE) for atoms and some small molecules [8][9][10][11][12][13][14][15][16][17][18][19], mostly based on the single-activeelectron (SAE) model. Calculations including all electrons in the atom or molecules have been used within the timedependent density functional theory (TDDFT) [20][21][22][23][24][25], the time-dependent Hartree-Fock (TDHF) theory [26,27], or the multiconfiguration time-dependent Hartree-Fock (MCTDHF) theory [28][29][30]. These calculations are very time-consuming and their accuracy is also difficult to judge.…”