Ionization of oriented targets by intense circularly polarized laser pulses: Imprints of orbital angular nodes in the 2D momentum distribution

TL;DR

This study uses ab initio simulations to show how circularly polarized laser pulses reveal the orbital angular node structure of atoms in photoelectron momentum distributions, offering insights into orbital symmetry.

Contribution

It demonstrates that ionization with circularly polarized pulses can map out the orbital angular nodal structure, providing a new method to study orbital symmetry.

Findings

Distinct signatures of orbital structure in momentum distributions

Carrier-envelope phase affects the distributions

Ionization maps orbital angular nodes

Abstract

We solve the three-dimensional time-dependent Schr\"{o}dinger equation for a few-cycle circularly polarized femtosecond laser pulse interacting with an oriented target exemplified by an Argon atom, initially in a $3\text{p}_{x}$ or $3\text{p}_{y}$ state. The photoelectron momentum distributions show distinct signatures of the orbital structure of the initial state as well as the carrier-envelope phase of the applied pulse. Our \textit{ab initio} results are compared with results obtained using the length-gauge strong-field approximation, which allows for a clear interpretation of the results in terms of classical physics. Furthermore, we show that ionization by a circularly polarized pulse completely maps out the angular nodal structure of the initial state, thus providing a potential tool for studying orbital symmetry in individual systems or during chemical reactions.