Effect of multielectron polarization in strong-field ionization of the oriented CO molecule

TL;DR

This paper demonstrates that incorporating multielectron polarization effects within the TDSE framework enhances the accuracy of modeling strong-field ionization of oriented CO molecules, especially by reducing dipole coupling to lower-lying states.

Contribution

It introduces a method to turn off the external field within a molecular radius to effectively include multielectron polarization effects in strong-field ionization simulations.

Findings

Multielectron polarization improves TDSE solutions for CO ionization.

Turning off the external field within a molecular radius reduces dipole coupling.

The approach accurately describes orientation-dependent ionization dynamics.

Abstract

We discuss the mechanism by which the inclusion of multielectron polarization improves the solution of the time-dependent Schr\"{o}dinger equation (TDSE) for the oriented CO molecule in a strong external laser pulse within the single-active-electron (SAE) approximation. A challenging problem of using the SAE approximation is that the active electron, instead of undergoing ionization, may be driven by the external field to lower-lying orbitals. For the oriented CO molecule, dipole coupling to the lower-lying bound states of the potential depends on the orientation angle, thereby affecting the orientation-dependent ionization dynamics. By including multielectron polarization, the external field is turned off within the molecular radius, thereby minimizing dipole coupling of the highest occupied molecular orbital to the lower-lying states of the potential. We discuss how turning off the external field within an appropriate molecular radius without accounting for the induced dipole term in the effective potential beyond this radial cut-off distance, constitutes an effective and accurate approach to describe strong-field ionization of CO and to minimize dipole coupling to lower-lying bound states.