Influence of the noninteracting density response function on the exchange-only kernel in time-dependent density-functional theory

Journal Article · Sun Oct 15 04:00:00 EDT 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.74.044502· OSTI ID:20863995

March, N H ^[1]; Niehaus, T A ^[2]; Suhai, S ^[3]

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1. Inorganic Chemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom)
2. Bremen Center for Computational Material Science, University of Bremen, D-28359 Bremen (Germany)
3. Department of Molecular Biophysics, German Cancer Research Center, D-69120 Heidelberg (Germany)

A formally exact expression for the interaction density response function {chi}(r,r{sup '},{omega}) exists in terms of (i) its noninteracting counterpart {chi}{sub 0}(r,r{sup '},{omega}) and (ii) an exchange (x)-correlation (c) kernel f{sub xc}(r,r{sup '},{omega}). In the absence of a first-principles theory for the {omega} dependence of f{sub xc}, the adiabatic approximation is most frequently made in this term, to construct a workable time-dependent density-functional theory. In the present study, a proposal is put forward to avoid the adiabatic approximation by working in the exchange-only limit in which f{sub xc} is set equal to f{sub x}(r,r{sup '},{omega}). We then refer to a result for the exchange energy given by Pines and Nozieres to motivate the assumption that f{sub x}=f{sub x}[Im {chi}{sub 0}(r,r{sup '},{omega})]. The essential proposal here is therefore that the integral equation to be solved for the interacting density response function {chi} is in the exchange-only case characterized entirely by the noninteracting response function {chi}{sub 0}.

• OSTI ID: 20863995
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 74; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ADIABATIC APPROXIMATION
CORRELATIONS
DENSITY
DENSITY FUNCTIONAL METHOD
INTEGRAL EQUATIONS
KERNELS
RESPONSE FUNCTIONS
TIME DEPENDENCE