Ionization of oriented carbonyl-sulfide molecules by intense circularly polarized laser pulses

TL;DR

This study combines experimental and theoretical approaches to investigate how intense circularly polarized laser pulses ionize oriented carbonyl-sulfide molecules, revealing asymmetries in electron emission influenced by molecular dipoles and Stark shifts.

Contribution

It provides new insights into the strong-field ionization of one-dimensionally-oriented polar molecules, highlighting the role of Stark shifts and molecular dipoles in electron emission asymmetries.

Findings

Pronounced asymmetries in photoelectron angular distributions perpendicular to dipole moments.

Explanation of asymmetries using a tunneling model with Stark shifts.

Focus on ionization behavior of one-dimensionally-oriented polar molecules.

Abstract

We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl-sulphide molecules by circularly-polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molecular electric dipole moment. These findings are explained by a tunneling model invoking the laser-induced Stark shifts associated with the dipoles and polarizabilities of the molecule and its unrelaxed cation. The focus of the present article is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons. In the following article (Phys. Rev. A 83, 023406 (2011)) the focus is to understand strong-field ionization from three-dimensionally-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals.