Angle-resolved time delay in photoemission

TL;DR

This paper explores the angular dependence of photoemission time delays in noble gases, revealing significant directional effects near Cooper minima, which could help resolve discrepancies between experimental and theoretical results.

Contribution

It introduces the theoretical investigation of directional dependence of photoemission time delays, especially near Cooper minima, extending previous studies on neon to argon.

Findings

Strong angular dependence of time delay in argon near Cooper minima

Discrepancy between measured and calculated delays in neon addressed

Directional effects are significant in photoemission timing

Abstract

We investigate theoretically the relative time delay of photoelectrons originating from different atomic subshells of noble gases. This quantity was measured via attosecond streaking and studied theoretically by Schultze et al. [Science 328, 1658 (2010)] for neon. A substantial discrepancy was found between the measured and the calculated values of the relative time delay. Several theoretical studies were put forward to resolve this issue, e.g., by including correlation effects. In the present paper we explore a further aspect, namely the directional dependence of time delay. In contrast to neon, for argon target a strong angular dependence of time delay is found near a Cooper minimum.