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

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.

40 pages, 10 figures, 3 tables

References in corpus (5)

• The Magnus expansion and some of its applications
• Perspective: Essentials of Relativistic Quantum Chemistry
• Accurate X-Ray Absorption Predictions for Transition Metal Oxides: An Advanced Self-Consistent-Field Approach Inspired by Many-Body Perturbation Theory
• Quantifying the error of the core-valence separation approximation
• Linear-response range-separated density-functional theory for atomic photoexcitation and photoionization spectra

Cited by in corpus (3)

• Density Functional Theory for Electronic Excited States
• Accurate Relativistic Real-Time Time-Dependent Density Functional Theory for Valence and Core Attosecond Transient Absorption Spectroscopy
• Fast simulation of soft x-ray near-edge spectra using a relativistic state-interaction approach: Application to closed-shell transition metal complexes