ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
For arbitrary k, the separation of spin variables is performed in the reduced density matrix of the kth order (RDM-k) on the basis of the Fock coordinate function method. The independent spatial components of RDM-k are analyzed. For RDM-k of the total spin eigenstate, their number is proved never to exceed its spin multiplicity 2s + 1. Integral and other nontrivial interrelations between spatial components are established which turn out to be the necessary and sufficient conditions of spin purity of a wavefunction corresponding to a given RDM-k. It is shown that the r-rank k-particle spin distribution matrix Fkr, defined as a spatial coefficient at the spin-tensorial operator of rank r in the RDM-k expansion, can be obtained by reduction of the (k + r)-particle charge density matrix Fk+r0. In particular, all spatial components of RDM-2 are explicitly expressed in terms of the four-electron charge density matrix only. This allows us to purpose some approximative formulas for the McWeeny-Mizuno spin-orbit and spin-spin coupling functions in the case of the weak spin contamination.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560200604
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