Center for Molecular Modeling - S. Verdonck

Characterization of the electron propagator with a GW-like self-energy in closed-shell atoms

wim — Mon, 03 Oct 2011 07:06:34 +0000

S. Verdonck, D. Van Neck, P.W. Ayers, M. Waroquier

Physical Review A

74 (6), 062503

2006

Abstract

The electron propagator is calculated for a set of closed-shell atoms using GW-like self-energies that contain the coupling of single-particle degrees of freedom with excited states in the framework of the random phase approximation. The effect of including exchange diagrams is investigated. Calculations are performed in the Hartree-Fock (HF) basis of the neutral atom. The HF continuum is taken into account using a discretization procedure, and the basis set limit is estimated using a systematic increase of basis set size. We check the approximation of taking the self-energy diagonal in the HF basis, and to what extent the extended Koopman’s theorem is fulfilled using an approximate self-energy. Finally we try to model the information contained in the propagator in terms of a functional containing Hartree-Fock quantities and demonstrate the feasibility of simultaneously reproducing the correlation and ionization energy of an underlying ab initio model.

DOI

http://dx.doi.org/10.1103/PhysRevA.74.062503

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06 physrev A 74 062503 verdonck.pdf

Quasiparticle properties in a density-functional framework

wim — Fri, 30 Sep 2011 14:46:53 +0000

D. Van Neck, S. Verdonck, G. Bonny, P.W. Ayers, M. Waroquier

Physical Review A

74 (4), 042501

2006

Abstract

We propose a framework to construct the ground-state energy and density matrix of an N-electron system by solving a self-consistent set of single-particle equations. The method can be viewed as a nontrivial extension of the Kohn-Sham scheme (which is embedded as a special case). It is based on separating the Green’s function into a quasiparticle part and a background part, and expressing only the background part as a functional of the density matrix. The calculated single-particle energies and wave functions have a clear physical interpretation as quasiparticle energies and orbitals.

DOI

http://dx.doi.org/10.1103/PhysRevA.74.042501

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06 physrev A 74 042501 van neck.pdf

Spectral functions in an exactly solvable self-bound A-body system

wim — Fri, 30 Sep 2011 13:39:12 +0000

D. Van Neck, S. Rombouts, S. Verdonck

Physical Review C

72 (5), 054318

2005

Abstract

We consider an exactly solvable Hamiltonian for bosons in one-dimension interacting through zero-range attractive forces, and construct a complete basis of its A-particle eigenstates. The structure of the single-particle spectral function in the removal domain is investigated, by taking the overlap of the A-particle ground state with the various excited states of the (A-1) system. In particular we study the contribution to the spectral function of the different break-up channels in the A-1 continuum, and compare the results to general statements available in the literature. It is shown that the asymptotic behavior in coordinate space does not agree with conventional assumptions. The relation to recent (e,e'p) experiments at large values of missing energy and momentum is pointed out.

DOI

http://dx.doi.org/10.1103/PhysRevC.72.054318

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05 phys. rev. C 72(5)054318 van neck.pdf

BOF / N24 DVN

wim — Wed, 15 May 2013 09:13:26 +0000

Project promotor

D. Van Neck

Financierende instantie

BOF / N24

Project data

01/09/2004 to 31/08/2008

Bedrag

€153 000,00

Project titel

New Classes of density functionals for electronic systems

Personeel

S. Verdonck, D. Vanfleteren

Coupling of electrons to RPA excitations in atoms

wim — Tue, 18 Oct 2011 08:30:38 +0000

S. Verdonck, D. Van Neck, V. Van Speybroeck, M. Waroquier

Poster

Conference / event / venue

DFT2005

Geneva, Switzerland

Sunday, 11 September, 2005 to Thursday, 15 September, 2005

Stijn Verdonck

wim — Thu, 25 Aug 2011 12:43:03 +0000