Time delay between photoemission from the 2p and 2s subshells of Neon

TL;DR

This study uses the RMT method to calculate photoemission time delays from neon's 2p and 2s orbitals, providing new theoretical insights and comparisons with experimental data for attosecond pulses.

Contribution

The paper introduces the application of the RMT method to compute photoemission time delays in neon, including correlated-electron effects and basis set improvements.

Findings

Time delay at 105.2 eV is 10.2 +/- 1.3 attoseconds.

Time delay at 89.8 eV is 14.5 +/- 1.5 attoseconds.

Results are somewhat larger than previous theories but smaller than experiments.

Abstract

The R-Matrix incorporating Time (RMT) method is a new method for solving the time-dependent Schroedinger equation for multi-electron atomic systems exposed to intense short-pulse laser light. We have employed the RMT method to investigate the time delay in the photoemission of an electron liberated from a 2p orbital in a neon atom with respect to one released from a 2s orbital following absorption of an attosecond XUV pulse. Time delays due to XUV pulses in the range 76-105 eV are presented. For an XUV pulse at the experimentally relevant 105.2 eV, we calculate the time delay to be 10.2 +/- 1.3 attoseconds, somewhat larger than estimated by other theoretical calculations, but still a factor two smaller than experiment. We repeated the calculation for a photon energy of 89.8 eV with a larger basis set capable of modelling correlated-electron dynamics within the neon atom and the residual Ne(+) ion. A time delay of 14.5 +/- 1.5 attoseconds was observed, compared to a 16.7 +/- 1.5 attosecond result using a single-configuration representation of the residual Ne(+) ion.