XUV ionization of the H$_2$ molecule studied with attosecond angular streaking

TL;DR

This paper investigates the orientation-dependent phase and time delays in XUV ionization of H$_2$ molecules using attosecond angular streaking, revealing two-center interference effects and potential well influences on photoelectron momentum.

Contribution

It applies attosecond angular streaking to H$_2$, demonstrating sensitive dependence of phase and delay on molecular orientation and analyzing two-center interference patterns.

Findings

Orientation-dependent phase and time delay in H$_2$ ionization

Observation of clear two-center interference patterns

Effective photoelectron momentum exceeds asymptotic momentum due to molecular potential

Abstract

We study orientation and two-center interference effects in attosecond time-resolved photoionization of the H$_2$ molecule. Time resolution of XUV ionization of H$_2$ is gained through the phase retrieval capability of attosecond angular streaking demonstrated earlier by Kheifets {\em et al} [arXiv:2202.06147 (2022)]. Once applied to H$_2$, this technique delivers an anisotropic phase and time delay which both depend sensitively on the molecular axis orientation. In addition, the photoelectron momentum distribution displays a very clear two-center interference pattern. When the interference formula due to Walter and Briggs [J. Phys. B {\bf 32} 2487 (1999)] is applied, an effective photoelectron momentum appears to be greater than the asymptotic momentum at the detector. This effect is explained by a molecular potential well surrounding the photoemission center.