Representing the thermal state in timedependent density functional theory
Classical molecular dynamics (MD) provides a powerful and widely used approach to determining thermodynamic properties by integrating the classical equations of motion of a system of atoms. TimeDependent Density Functional Theory (TDDFT) provides a powerful and increasingly useful approach to integrating the quantum equations of motion for a system of electrons. TDDFT efficiently captures the unitary evolution of a manyelectron state by mapping the system into a fictitious noninteracting system. In analogy to MD, one could imagine obtaining the thermodynamic properties of an electronic system from a TDDFT simulation in which the electrons are excited from their ground state by a timedependent potential and then allowed to evolve freely in time while statistical data are captured from periodic snapshots of the system. For a variety of systems (e.g., many metals), the electrons reach an effective state of internal equilibrium due to electronelectron interactions on a time scale that is short compared to electronphonon equilibration. During the initial timeevolution of such systems following electronic excitation, electronphonon interactions should be negligible, and therefore, TDDFT should successfully capture the internal thermalization of the electrons. However, it is unclear how TDDFT represents the resulting thermal state. In particular, the thermal state is usually representedmore »
 Authors:

^{[1]};
^{[2]}
 Sandia National Laboratories, Albuquerque, New Mexico 871851315 (United States)
 Advanced Logic Lab, Samsung Semiconductor, Inc., Austin, Texas 78754 (United States)
 Publication Date:
 OSTI Identifier:
 22415864
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ATOMS; CAPTURE; COMPARATIVE EVALUATIONS; DENSITY FUNCTIONAL METHOD; ELECTRONELECTRON COUPLING; ELECTRONPHONON COUPLING; ELECTRONS; EQUATIONS OF MOTION; EXCITATION; GROUND STATES; MANYBODY PROBLEM; MIXED STATE; MIXED STATES; MOLECULAR DYNAMICS METHOD; PURE STATES; QUANTUM MECHANICS; THERMALIZATION; THERMODYNAMIC PROPERTIES; TIME DEPENDENCE; WAVE FUNCTIONS