Exploring High-Order Harmonic Generation in Neon using the R-Matrix with Time-Dependence Method*

We report results concerning high-order harmonic generation (HHG) from neon atoms using the R-Matrix with time dependence method (RMT) [1]. For this study, which is a follow-up on earlier work [2], the harmonics are produced by a few-cycle 800 nm driving laser with a peak intensity of 2x10¹⁴ W/cm². Several different pulse durations are employed. The RMT calculations are checked for convergence with respect to several parameters, including the atomic structure description, the size of the total angular-momentum expansion, numerical parameters including the time-step and grid spacing, as well as inner- and outer-region box sizes. Comparison between different computational methods, particularly when the HHG spectrum is calculated in absolute units [2,3], is a valuable tool for providing benchmark data, as well as determining limitations of software suites. The goal of this work is to produce an initial set of converged RMT calculations, which can be used for future comparisons.

 

[1] A. C. Brown et al., Comp. Phys. Commun. 250 (2020) 107062

[2] K. Finger, D. Atri-Schuller, N. Douguet, K. Bartschat, and K. R. Hamilton, Phys. Rev. A 106 (2022) 063113

[3] A. T. Bondy et al., https://arxiv.org/abs/2311.03677 (2023)