Theory of the inhomogeneous electron gas.
Item
-
Title
-
Theory of the inhomogeneous electron gas.
-
Identifier
-
AAI9020767
-
identifier
-
9020767
-
Creator
-
Harbola, Manoj Kumar.
-
Contributor
-
Adviser: Viraht Sahni
-
Date
-
1990
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Physics, Condensed Matter | Physics, Atomic
-
Abstract
-
In this thesis we present a physical interpretation for the local many-body (exchange-correlation) potential of Hohenberg-Kohn-Sham density-functional theory of the interacting inhomogeneous electron gas. Thus far this potential has been known only in terms of its mathematical definition as the functional derivative of the yet unknown exchange-correlation energy functional. We interpret the potential as the work done in moving an electron in the electric field produced by its Fermi-Coulomb hole charge distribution. Thus, with this interpretation this potential is obtained directly from the Fermi-Coulomb hole, the requirement of determining the functional derivatives being obviated. Within the exchange-only approximation, the potential derived by our interpretation is shown analytically to satisfy the virial theorem sum rule for the exact exchange energy functional, a necessary condition for the exchange potentials of density-functional theory, as well as all scaling properties of such potentials. A significant consequence of the interpretation is that the asymptotic structure of the exchange-correlation potential is shown to be due to Pauli correlation effects alone, and therefore can be determined exactly. The interpretation also provides the explanation as to why the Slater potential is incorrect. The formalism is applied to closed subshell atoms and jellium metal surfaces within the exchange-only approximation. The self-consistently determined total ground-state energies of atoms are rigorous upper bounds to and lie within 50 ppm of the results of Hartree-Fock theory. Furthermore, since the exchange potential is the exact exchange-correlation potential in the outer and asymptotic regions of the atom, the highest occupied eigenvalues more closely approximate the experimental ionization potential, and asymptotically the potential goes as -(1/r). For jellium metal surfaces it is shown that for asymptotic positions of the electron the exchange potential goes as the image potential -(1/4x). Inside the metal, the exchange potential is lowered to a value of -{dollar}2\over3{dollar} (in units of 3k{dollar}\sb{lcub}F{rcub}{dollar}/2{dollar}\pi{dollar}), the exact homogeneous electron gas result of Kohn-Sham theory.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
