Cluster studies of La[sub 2]CuO[sub 4]: CuO[sub 6]

Journal Article · Tue Jun 01 00:00:00 EDT 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.464475· OSTI ID:6669111

Martin, R L; Hay, P J ^[1]

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1. Theoretical Division, MSB268, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

We present the results of [ital ab] [ital initio] calculations for a CuO[sub 6] cluster embedded in a background potential appropriate for La[sub 2]CuO[sub 4]. These calculations differ from prior work in that an improved embedding potential for the cluster is utilized which enforces orthogonality between the cluster electrons and the background point charges. This is accomplished through the use of effective core potentials to represent the point charges nearest the CuO[sub 6] cluster. The major qualitative change this brings about is a destabilization of the Cu4[ital s] level relative to the Cu3[ital d] orbital. The cluster results for [ital n] doping now give a 3[ital d][sup 10] configuration for Cu as opposed to the 3[ital d][sup 9]4[ital s] configuration observed in earlier work. In addition, much more extensive treatments of electron correlation have been examined using the technique of configuration interaction (CI). Results for [ital n]-doped, undoped, and [ital p]-doped clusters are presented. The ligand [r arrow]metal charge transfer excitations, the crystal-field spectrum, and the photoemission spectrum are discussed. Special attention is given to the characterization of the wave function for the [ital p]-doped cluster. While the loss in electron density is almost entirely from the O2[ital p][sub [sigma]] orbital, in agreement with experiment, it is shown that the wave function is closer to the independent-particle molecular orbital'' limit than the valence-bond'' local singlet, and that a description of the cluster ion ground states in terms of the occupation of a single effective'' Cu 3[ital d] orbital is possible.

• OSTI ID: 6669111
• Journal Information: Journal of Chemical Physics; (United States), Vol. 98:11; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LANTHANUM COMPOUNDS
ELECTRONIC STRUCTURE
ATOMIC CLUSTERS
CLUSTER MODEL
CUPRATES
N-TYPE CONDUCTORS
P-TYPE CONDUCTORS
POTENTIALS
COPPER COMPOUNDS
MATERIALS
MATHEMATICAL MODELS
NUCLEAR MODELS
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
SEMICONDUCTOR MATERIALS
TRANSITION ELEMENT COMPOUNDS
360207* - Ceramics
Cermets
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