Tight-binding Electron-ion Dynamics: A Method for treating nonadiabatic processes and Interactions with Electromagnetic Radiation

1997 ◽  
Vol 491 ◽  
Author(s):  
J. S. Graves ◽  
R. E. Allen
Keyword(s):  
Electromagnetic Radiation ◽  
Radiation Field ◽  
Schrodinger Equation ◽  
Tight Binding ◽  
Time Dependent ◽  
Ion Dynamics ◽  
Coupled Dynamics ◽  
Electrons And Ions ◽  
Ehrenfest Theorem ◽  
Intense Radiation

ABSTRACTA method is introduced for simulations of the coupled dynamics of electrons and ions in a molecule or material. It is applicable to general nonadiabatic processes, including interactions with an arbitrarily intense radiation field. The field is included in the electronic Hamiltonian through a time-dependent Peierls substitution. The time-dependent Schrödinger equation is solved with an algorithm that preserves orthogonality, and the atomic forces are obtained from a generalized Ehrenfest theorem. Calculations for GaAs and Si demonstrate that the method is reliable and quantitative.

TIME-DEPENDENT EVOLUTION OF A WAVE PACKET IN QUANTUM SYSTEMS

2008 ◽  
Vol 22 (24) ◽  
pp. 4225-4241
Author(s):  
CHI-SHUNG TANG ◽  
PI-GANG LUAN
Keyword(s):  
Charged Particle ◽  
General Solution ◽  
Schrödinger Equation ◽  
Wave Packet ◽  
Particle Motion ◽  
Schrodinger Equation ◽  
Quantum Systems ◽  
Time Dependent ◽  
Ehrenfest Theorem ◽  
Charged Particle Motion

We consider wave packet propagation in mesoscopic quantum systems. A number of approaches are compared to look at the general solution of a time-dependent Schrödinger equation and the validity of the Ehrenfest theorem. Detailed calculations are presented to illustrate the results of a charged particle motion in the time-dependent systems, and show that the Ehrenfest theorem is not directly applicable in topologically nontrivial systems.

Introduction

2018 ◽  
Author(s):  
Niels Engholm Henriksen ◽  
Flemming Yssing Hansen
Keyword(s):  
Schrödinger Equation ◽  
Schrodinger Equation ◽  
Degrees Of Freedom ◽  
State Level ◽  
Boltzmann Distribution ◽  
Theoretical Description ◽  
Time Dependent ◽  
Nuclear Dynamics ◽  
Molecular Reaction ◽  
Oppenheimer Approximation

This introductory chapter considers first the relation between molecular reaction dynamics and the major branches of physical chemistry. The concept of elementary chemical reactions at the quantized state-to-state level is discussed. The theoretical description of these reactions based on the time-dependent Schrödinger equation and the Born–Oppenheimer approximation is introduced and the resulting time-dependent Schrödinger equation describing the nuclear dynamics is discussed. The chapter concludes with a brief discussion of matter at thermal equilibrium, focusing at the Boltzmann distribution. Thus, the Boltzmann distribution for vibrational, rotational, and translational degrees of freedom is discussed and illustrated.

Impact of vibronic coupling effects on light-driven charge transfer in pyrene-functionalized middle and large-sized Metalloid Gold Nanoclusters from Ehrenfest dynamics.

2021 ◽  
Author(s):  
Adrian Dominguez-Castro ◽  
Thomas Frauenheim
Keyword(s):  
Molecular Dynamics ◽  
Charge Transfer ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Gold Nanoclusters ◽  
Tight Binding ◽  
Time Dependent ◽  
Effective Strategy ◽  
Dynamics Simulations ◽  
Dependent Density

Theoretical calculations are an effective strategy to comple- ment and understand experimental results in atomistic detail. Ehrenfest molecular dynamics simulations based on the real-time time-dependent density functional tight-binding (RT-TDDFTB) approach...

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