首页>
外文期刊>journal of chemical physics
>Semirigorous LCAOmdash;MOmdash;SCF Methods for Threehyphen;Dimensional Molecular Calculations Including Electron Repulsion
【24h】
Semirigorous LCAOmdash;MOmdash;SCF Methods for Threehyphen;Dimensional Molecular Calculations Including Electron Repulsion
展开▼
机译：Semirigorous LCAOmdash;MOmdash;SCF Methods for Threehyphen;Dimensional Molecular Calculations Including Electron Repulsion
A semirigorous LCAOmdash;MOmdash;SCF method including electron repulsion, for threehyphen;dimensional closedhyphen;shell molecular calculations has been derived. The method starts with the complete manyhyphen;electron Hamiltonian (in which interelectronic interactions are included explicitly) and the selfhyphen;consistent molecular orbital equations of Roothaan, then makes a series of systematic approximations for the integrals involved. There are several different levels of approximation which evolve depending on how restrictive one makes the conditions for neglectingaprime;(1)aPrime;(1), whereaprime; andaPrime; are two orbitals on Atom A; andaprime;(1)bPrime;(1), whereais an orbital on Atom A andbis an orbital on Atom B,A ne; B, and for neglecting (aprime;cprime;prime;prime;verbar;Gverbar;bPrime;dprime;v), whereaprime; is an orbital on Atom A,bPrime; is an orbital on Atom B,cprime;prime;prime; is an orbital on Atom C,dprime;vis an orbital on Atom D, and A, B, C, D are, in general, different atoms. The approximations for the core operators are defined and the core Hamiltonian matrix elements are presented in detail for several of the levels of approximation. The complete expressions forFaprime;aprime;, Faprime;aPrime;, andFaprime;bPrime;for closedhyphen;shell systems in the two simplest of the approximative schemes are included in the body of this paper. The salient details of the more complicated schemes (corresponding to lesser and lesser neglect of the interaction of charge distributions) are indicated.These semirigorous LCAOmdash;MOmdash;SCF schemes outlined in this paper hold promise for lesshyphen;thanhyphen;rigorous yet betterhyphen;thanhyphen;empirical calculations for the whole gamut of threehyphen;dimensional molecules from simple inorganics through complicated organics. An analogous treatment with the same approximations for the neglect of certain integrals can also be applied to an openhyphen;shell LCAOmdash;MOmdash;SCF procedure.
展开▼
