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Traces of spin‐adapted reduced density matrices
Author(s) -
PérezRomero E.,
Tel L. M.,
Valdemoro C.
Publication year - 1997
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/(sici)1097-461x(1997)61:1<55::aid-qua6>3.0.co;2-3
Subject(s) - rdm , eigenvalues and eigenvectors , order (exchange) , spin (aerodynamics) , physics , quantum mechanics , theoretical physics , computer science , thermodynamics , computer network , finance , economics
The traces of the p ‐order reduced density matrices ( p ‐RDM) split into independent contributions associated to the subsets of p ‐electron eigenstates of the Ŝ 2 and Ŝ z operators. Here, we report the partial traces for the blocks of the low‐order RDMs corresponding to pure spin states of an N ‐electron system. A systematic method for calculating those of higher order RDMs is described and some useful relations are also given. All these relations which must be fulfilled independently by a RDM can be considered as N ‐ and S ‐representability conditions © 1997 John Wiley & Sons, Inc.