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arXiv · 2202.06064

Self-Adaptive Real-Time Time-Dependent Density Functional Theory for X-ray Absorptions

Linfeng Ye·Hao Wang·Yong Zhang·Wenjian Liu
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Abstract

Real-time time-dependent density functional theory (RT-TDDFT) can in principle access the whole absorption spectrum of a many-electron system exposed to a narrow pulse. However, this requires an accurate and efficient propagator for the numerical integration of the time-dependent Kohn-Sham equation. While a low-order time propagator is already sufficient for the low-lying valence absorption spectra, it is no longer the case for the X-ray absorption spectra (XAS) of systems composed even only of light elements, for which the use of a high-order propagator is indispensable. It is then crucial to choose a largest possible time step and a shortest possible simulation time, so as to minimize the computational cost. To this end, we propose here a robust AutoPST approach to determine automatically (Auto) the propagator (P), step (S), and time (T) for relativistic RT-TDDFT simulations of XAS.

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Linfeng Ye, Hao Wang, Yong Zhang, Wenjian Liu. 2022-02-12. Self-Adaptive Real-Time Time-Dependent Density Functional Theory for X-ray Absorptions. https://doi.org/10.1063/5.0106250

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