Velocity-gauge real-time TDDFT within a numerical atomic orbital basis set

TL;DR

This paper presents an implementation of velocity-gauge real-time TDDFT using a linear combination of atomic orbitals, enabling efficient simulation of electron dynamics in solids under laser fields and comparison with other methods.

Contribution

It introduces a novel LCAO-based implementation of velocity-gauge RT-TDDFT for solid-state electron dynamics, expanding computational tools for laser-matter interaction studies.

Findings

LCAO implementation accurately reproduces electronic responses to laser fields.

Comparison shows consistency with real-space grid and APW methods.

Potential for studying core-electronic excitations in spectroscopies.

Abstract

The interaction of laser fields with solid-state systems can be modeled efficiently within the velocity-gauge formalism of real-time time dependent density functional theory (RT-TDDFT). In this article, we discuss the implementation of the velocity-gauge RT-TDDFT equations for electron dynamics within a linear combination of atomic orbitals (LCAO) basis set framework. Numerical results obtained from our LCAO implementation, for the electronic response of periodic systems to both weak and intense laser fields, are compared to those obtained from established real-space grid and Full-Potential Linearized Augumented Planewave approaches. Potential applications of the LCAO based scheme in the context of extreme ultra-violet and soft X-ray spectroscopies involving core-electronic excitations are discussed.