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Correlated electron dynamics and memory in time-dependent density functional theory

Abstract

Time-dependent density functional theory (TDDFT) is an exact reformulation of the time-dependent many-electron Schroedinger equation, where the problem of many interacting electrons is mapped onto the Kohn-Sham system of noninteracting particles which reproduces the exact electronic density. In the Kohn-Sham system all non-classical many-body effects are incorporated in the exchange-correlation potential which is in general unknown and needs to be approximated. It is the goal of this thesis to investigate the connection between memory effects and correlated electron dynamics in strong and weak fields. To this end one-dimensional two-electron singlet systems are studied. At the same time these systems include the onedimensional helium atom model, which is an established system to investigate the crucial effects of correlated electron dynamics in external fields. The studies presented in this thesis show that memory effects are negligible for typical strong field processes. Here the approximation of the spatial nonlocality is of primary importance. For the photoabsorption spectra on the other hand the neglect of memory effects leads to qualitative and quantitative errors, which are shown to be connected to transitions of double excitation character. To develop a better understanding of the conditions under which memory effects become important quantum fluid dynamics has been  More>>
Authors:
Publication Date:
Jul 28, 2009
Product Type:
Thesis/Dissertation
Report Number:
INIS-DE-0848
Resource Relation:
Other Information: TH: Diss. (Dr.rer.nat.)
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DENSITY FUNCTIONAL METHOD; SCHROEDINGER EQUATION; ELECTRON CORRELATION; HELIUM; ATOMS; ABSORPTION SPECTRA; QUANTUM FLUIDS; TWO-BODY PROBLEM; ELECTRONIC STRUCTURE; EXCHANGE INTERACTIONS; ONE-DIMENSIONAL CALCULATIONS; PHOTON COLLISIONS; FLUID MECHANICS; ELECTRON DENSITY
OSTI ID:
21246474
Research Organizations:
Bayreuth Univ. (Germany)
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
TRN: DE09FE063
Availability:
Commercial reproduction prohibited; INIS; OSTI as DE21246474
Submitting Site:
DEN
Size:
106 pages
Announcement Date:
Dec 19, 2009

Citation Formats

Thiele, Mark. Correlated electron dynamics and memory in time-dependent density functional theory. Germany: N. p., 2009. Web.
Thiele, Mark. Correlated electron dynamics and memory in time-dependent density functional theory. Germany.
Thiele, Mark. 2009. "Correlated electron dynamics and memory in time-dependent density functional theory." Germany.
@misc{etde_21246474,
title = {Correlated electron dynamics and memory in time-dependent density functional theory}
author = {Thiele, Mark}
abstractNote = {Time-dependent density functional theory (TDDFT) is an exact reformulation of the time-dependent many-electron Schroedinger equation, where the problem of many interacting electrons is mapped onto the Kohn-Sham system of noninteracting particles which reproduces the exact electronic density. In the Kohn-Sham system all non-classical many-body effects are incorporated in the exchange-correlation potential which is in general unknown and needs to be approximated. It is the goal of this thesis to investigate the connection between memory effects and correlated electron dynamics in strong and weak fields. To this end one-dimensional two-electron singlet systems are studied. At the same time these systems include the onedimensional helium atom model, which is an established system to investigate the crucial effects of correlated electron dynamics in external fields. The studies presented in this thesis show that memory effects are negligible for typical strong field processes. Here the approximation of the spatial nonlocality is of primary importance. For the photoabsorption spectra on the other hand the neglect of memory effects leads to qualitative and quantitative errors, which are shown to be connected to transitions of double excitation character. To develop a better understanding of the conditions under which memory effects become important quantum fluid dynamics has been found to be especially suitable. It represents a further exact reformulation of the quantum mechanic many-body problem which is based on hydrodynamic quantities such as density and velocity. Memory effects are shown to be important whenever the velocity field develops strong gradients and dissipative effects contribute. (orig.)}
place = {Germany}
year = {2009}
month = {Jul}
}