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Electronic structure of crystals: Embedded quantum cluster with overlap
Author(s) -
Vail John M.,
Rao Bijan K.
Publication year - 1995
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560530110
Subject(s) - embedding , fock space , coupled cluster , cluster (spacecraft) , quantum mechanics , eigenvalues and eigenvectors , wave function , physics , chemistry , computational chemistry , statistical physics , molecule , computer science , artificial intelligence , programming language
We consider a crystal as partitioned into a localized molecular cluster (containing a defect or not) and an embedding region. Within the Hartree–Fock formalism, an expression is derived for an effective potential due to the embedding region of crystal. This potential is part of the cluster Fock operator and requires input from a perfect crystal calculation. Special features of the derivative are rigorous inclusion of cluster‐embedding overlap and orthogonality between single‐electron states of the embedding region and the function‐space manifold of the cluster; physically correct normalization of the Fock eigenstates; and a nontrivial total‐energy algorithm. Computational requirements are qualitatively compared with those for an isolated cluster. The method allows for intracluster (and intraembedding) correlation and can be adapted straightforwardly to local density functional approaches. Fundamental aspects of the embedding problem are addressed in a general formulation that is, nevertheless, oriented toward explicit calculations. © 1995 John Wiley & Sons, Inc.