Realtime time-dependent density-functional theory (RT-TDDFT) is one of the most practical techniques available to simulate electronic dynamics of molecules and materials. Promising applications of RT-TDDFT to study nonlinear spectra and energy transport demand simulations of large solvated systems over long time scales, which are computationally quite costly. In this paper, we apply an embedding technique developed for ground-state SCF methods by Manby and Miller to accelerate realtime TDDFT. We assess the accuracy and speed of these approximations by studying the absorption spectra of solvated and covalently split chromophores. Our embedding approach is also compared with less accurate, less costly QM/MM charge embeddings. We find that by mixing levels of detail the embedded mean-field theory scheme is a simple, accurate, and effective way to accelerate RT-TDDFT simulations.
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http://dx.doi.org/10.1021/acs.jctc.7b00494 | DOI Listing |
J Chem Theory Comput
December 2024
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
We present an application of our new theoretical formulation of quantum dynamics, moment propagation theory (MPT) (Boyer et al., J. Chem.
View Article and Find Full Text PDFNanophotonics
November 2024
Universite Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, UMR5306, F-69100, Villeurbanne, France.
In view of the recent increased interest in light-induced manipulation of magnetism in nanometric length scales this work presents metal clusters as promising elementary units for generating all-optical ultrafast magnetization. We perform a theoretical study of the opto-magnetic properties of metal clusters through ab-initio real-time (RT) simulations in real-space using time-dependent density functional theory (TDDFT). Through ab-initio calculations of plasmon excitation with circularly polarized laser pulse in atomically precise clusters of simple and noble metals, we discuss the generation of orbital magnetic moments due to the transfer of angular momentum from light field through optical absorption at resonance energies.
View Article and Find Full Text PDFJ Chem Theory Comput
December 2024
College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, The People's Republic of China.
Recently, we proposed a method to generalize collinear functionals to noncollinear functionals, called multicollinear approach, which has been applied in density functional theory (DFT) and linear-response time-dependent DFT (TDDFT) for the ground state and excited states calculations, respectively. In this work, we demonstrate the application of this method in real-time TDDFT by simulating electronic absorption spectra, Rabi resonance, and precession of a two-magnetic center system. Thanks to the nonvanishing local exchange-correlation torque provided by multicollinear functionals, research into the torques in the evolution of magnetization vector is carried out, which is useful for the exploration on spin dynamics.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
The enzyme ribonucleotide reductase plays a critical role in DNA synthesis and repair. Its mechanism requires long-range radical transfer through a series of proton-coupled electron transfer (PCET) steps. Nuclear quantum effects such as zero-point energy, proton delocalization, and hydrogen tunneling are known to be important in PCET.
View Article and Find Full Text PDFJ Chem Phys
November 2024
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
We present a Lagrangian-based implementation of Ehrenfest dynamics with nuclear-electronic orbital (NEO) theory and real-time time-dependent density functional theory for extended periodic systems. In addition to a quantum dynamical treatment of electrons and selected protons, this approach allows for the classical movement of all other nuclei to be taken into account in simulations of condensed matter systems. Furthermore, we introduce a Lagrangian formulation for the traveling proton basis approach and propose new schemes to enhance its application for extended periodic systems.
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