Klein, D. J.García Bach, Ma. de los Ángeles2009-10-202009-10-2019790163-1829https://hdl.handle.net/2445/9725Ground-state instability to bond alternation in long linear chains is considered from the point of view of valence-bond (VB) theory. This instability is viewed as the consequence of a long-range order (LRO) which is expected if the ground state is reasonably described in terms of the Kekulé states (with nearest-neighbor singlet pairing). It is argued that the bond alternation and associated LRO predicted by this simple, VB picture is retained for certain linear Heisenberg models; many-body VB calculations on spin s=1 / 2 and s=1 chains are carried out in a test of this argument.10 p.application/pdfeng(c) The American Physical Society, 1979MagnetismeValència (Química)ClústersMagnetismValence (Theoretical chemistry)Clústersinfo:eu-repo/semantics/article3447info:eu-repo/semantics/openAccess