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Spatial partitioning of the molecular wave function: Reexamination of the bond‐charge model of covalent binding
Author(s) -
Camparo James
Publication year - 2004
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.20172
Subject(s) - wave function , diatomic molecule , statistical physics , quantum chemistry , dissociation (chemistry) , computation , quantum , chemistry , bond dissociation energy , charge (physics) , computational chemistry , simple (philosophy) , physics , quantum mechanics , molecule , computer science , algorithm , philosophy , epistemology , supramolecular chemistry
Owing to the complexity of many‐body quantum interactions, theoretical problems in chemistry almost always necessitate numerical methods of solution. In turn, and somewhat paradoxically, this reliance on computation often precipitates a need for approximate models that can provide a conceptual framework for the interpretation of the accurate numerical solutions. In this report, we reexamine and improve upon the simple bond‐charge (SBC) model of Parr and Borkman with the express purpose of examining its role as a suitable intuitive model for bonding energetics. We first discuss the role of spatial partitioning in the SBC model and the molecular‐structure approximations that are implicit within the model. We then develop an improved version of the model by including electrostatic repulsion between shared electron pairs; we refer to this enhanced version as a semiempirical charge‐cloud (SCC) model. Applying the SCC model to a broad range of diatomics, we find that it is able to predict dissociation energies on a par with simple variational calculations. As an illustrative application of the SCC model, we use it to estimate unknown dissociation energies and rotational constants for a number of alkali dimers. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004