Assessment of the LFAs-PBE exchange-correlation potential for high-order harmonic generation of aligned H2+ molecules

TL;DR

This study evaluates the LFAs-PBE exchange-correlation potential's effectiveness in simulating high-order harmonic generation in aligned H2+ molecules using RT-TDDFT, showing it outperforms traditional potentials due to its correct asymptote.

Contribution

The paper demonstrates that LFAs-PBE, with a similar computational cost to PBE, significantly improves HHG spectral predictions by accurately modeling the XC potential's asymptote.

Findings

LFAs-PBE outperforms conventional XC potentials in HHG spectra.

The potential accurately captures properties sensitive to the XC asymptote.

LFAs-PBE is computationally efficient, suitable for large systems.

Abstract

We examine the performance of our recently developed LFAs-PBE exchange-correlation (XC) potential [C.-R. Pan, P.-T. Fang, and J.-D. Chai, Phys. Rev. A, 2013, 87, 052510] for the high-order harmonic generation (HHG) spectra and related properties of H2+ molecules aligned parallel and perpendicular to the polarization of an intense linearly polarized laser pulse, employing the real-time formulation of time-dependent density functional theory (RT-TDDFT). The results are compared with the exact solutions of the time-dependent Schrodinger equation as well as those obtained with other XC potentials in RT-TDDFT. Owing to its correct (-1/r) asymptote, the LFAs-PBE potential significantly outperforms conventional XC potentials for the HHG spectra and the properties that are sensitive to the XC potential asymptote. Accordingly, the LFAs-PBE potential, which has a computational cost similar to that of the popular Perdew-Burke-Ernzerhof (PBE) potential, can be very promising for the study of the ground-state, excited-state, and time-dependent properties of large electronic systems, extending the applicability of density functional methods for a diverse range of applications.