Torsional effects in strong-field ionization of molecules

Andrey I Dnestryan,Lars Bojer Madsen,Oleg I Tolstikhin,Frank Jensen

doi:10.1103/physrevresearch.1.023018

Abstract

This paper elucidates effects of torsional motion on tunneling ionization in intense laser fields. Recent advances in the formulation and implementation of an integral representation of the weak-field asymptotic theory make it possible to study the behavior of the tunneling ionization rate with the dihedral angle between the two planes in biphenyl and substituted biphenyl molecules. These results have implications for control of torsional motion and deracemization schemes for axial chiral molecules.

Highlights

Ionization by a tunnelinglike process is key in much of strong-field and attosecond physics [1]
We report a strong variation of the ionization rates with dihedral angle with contributions from several orbitals and a large difference between biphenyl and substituted biphenyl related to the permanent dipole of the latter system
We focus on two directions of the external electric field with respect to the field: (i) along the most polarizable axis (MPA), which is along the C-C bond connecting the two rings, and (ii) along the second most polarizable axis (SMPA), which is perpendicular to the MPA

Summary

INTRODUCTION

Ionization by a tunnelinglike process is key in much of strong-field and attosecond physics [1]. The possibility for laser-induced enantiomeric conversion of DFDBrBPh based on dynamic Stark control was investigated theoretically [40,41], including considerations of possibilities associated with invoking of artificial neural networks [42] In the latter theoretical studies, the intensities considered were up to tens of TW/cm, but the role of ionization in the dynamics was not considered. Implementation of the tail representation of the WFAT, or any other tunneling theory based on wave functions at large distance, for polyatomic molecules is technically extremely demanding To resolve this issue, the integral representation of the WFAT was developed [44] The possibility of determining accurate ionization rates for biphenyl and substituted biphenyl as a function of dihedral angle is relevant for experimental studies resolving laserinduced torsional motion by strong-field Coulomb explosion [36,37,38,39].

WEAK-FIELD ASYMPTOTIC THEORY

RESULTS AND DISCUSSION

Torsional and alignment effects in strong-field ionization of biphenyl

Torsional and orientational effects in strong-field ionization of DFDBrBPh

CONCLUSION AND OUTLOOK