Laser induced electron diffraction: a tool for molecular orbital imaging

TL;DR

This paper demonstrates that laser-induced electron diffraction can be used to image molecular orbitals and determine inter-atomic distances in molecules like N2 and CO2 with high accuracy using quantum simulations.

Contribution

It introduces a method to extract molecular geometrical and orbital information from laser-induced electron diffraction patterns through quantum simulations and a simple inversion algorithm.

Findings

Inter-atomic distances can be measured with a few percent accuracy.

Quantum interference patterns reveal molecular orbital structures.

The method works for molecules aligned perpendicular to the laser polarization.

Abstract

We explore the laser-induced ionization dynamics of N2 and CO2 molecules subjected to a few-cycle, linearly polarized, 800\,nm laser pulse using effective two-dimensional single active electron time-dependent quantum simulations. We show that the electron recollision process taking place after an initial tunnel ionization stage results in quantum interference patterns in the energy resolved photo-electron signals. If the molecule is initially aligned perpendicular to the field polarization, the position and relative heights of the associated fringes can be related to the molecular geometrical and orbital structure, using a simple inversion algorithm which takes into account the symmetry of the initial molecular orbital from which the ionized electron is produced. We show that it is possible to extract inter-atomic distances in the molecule from an averaged photon-electron signal with an accuracy of a few percents.