2026-04-13T05:47:06Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1997492025-12-04T20:48:29Zcom_2072_1057col_2072_478822col_2072_478917

00925njm 22002777a 4500 dc Klein, D.J. author García Bach, Ma. de los Ángeles author 2023-06-23T16:45:59Z 2023-06-23T16:45:59Z 1976 2023-06-23T16:45:59Z Cluster expanded wavefunctions involving localized‐site states and only pair excitations between nearest neighbor sites are considered. In the case that the bonds connecting these nearest neighbor sites form a tree graph (without rings), exact matrix element formulas are obtained in terms of the inverse of a modified type of topological matrix associated with this tree graph. The treatment of some near‐tree cases, without any touching rings, is also discussed. Termodinàmica estadística Teoria de grafs Arbres Statistical thermodynamics Graph theory Trees Variational localized-site cluster expansions. II. Trees and near trees