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Title: Quantal density-functional theory of excited states: The state arbitrariness of the model noninteracting system

The quantal density-functional theory (Q-DFT) of nondegenerate excited-states maps the pure state of the Schroedinger equation to one of noninteracting fermions such that the equivalent excited state density, energy, and ionization potential are obtained. The state of the model S system is arbitrary in that it may be in a ground or excited state. The potential energy of the model fermions differs as a function of this state. The contribution of correlations due to the Pauli exclusion principle and Coulomb repulsion to the potential and total energy of these fermions is independent of the state of the S system. The differences are solely a consequence of correlation-kinetic effects. Irrespective of the state of the S system, the highest occupied eigenvalue of the model fermions is the negative of the ionization potential. In this paper we demonstrate the state arbitrariness of the model system by application of Q-DFT to the first excited singlet state of the exactly solvable Hookean atom. We construct two model S systems: one in a singlet ground state (1s{sup 2}), and the other in a singlet first excited state (1s2s). In each case, the density and energy determined are equivalent to those of the excited state ofmore » the atom, with the highest occupied eigenvalues being the negative of the ionization potential. From these results we determine the corresponding Kohn-Sham density-functional theory (KS-DFT) 'exchange-correlation' potential energy for the two S systems. Further, based on the results of the model calculations, suggestions for the KS-DFT of excited states are made.« less
Authors:
 [1] ; ;  [2] ;  [2] ;  [3]
  1. Sacred Heart University, 5151 Park Avenue, Fairfield, Connecticut 06825 (United States)
  2. Graduate School, City University of New York, 365 Fifth Avenue, New York, New York 10016 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
20640322
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 68; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevA.68.042504; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; CORRELATIONS; COULOMB FIELD; DENSITY FUNCTIONAL METHOD; EIGENFUNCTIONS; EIGENVALUES; ENERGY DENSITY; EXACT SOLUTIONS; EXCITED STATES; FERMIONS; GROUND STATES; IONIZATION POTENTIAL; PAULI PRINCIPLE; POTENTIAL ENERGY; POTENTIALS; SCHROEDINGER EQUATION