Static spin correlations in alternant quantum cell models

Ramasesha, S. ; Soos, Z. G. (1985) Static spin correlations in alternant quantum cell models Physical Review B: Condensed Matter and Materials Physics, 32 (8). pp. 5368-5374. ISSN 1098-0121

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Official URL: http://prb.aps.org/abstract/PRB/v32/i8/p5368_1

Related URL: http://dx.doi.org/10.1103/PhysRevB.32.5368

Abstract

Static-spin-correlation functions 4<spzsqz> are evaluated via diagrammatic valence-bond theory for exact states of finite Hubbard, Pariser-Parr-Pople (PPP), and related quantum cell models. Several properties of <spzsqz> that are independent of intersite potentials Vpp' in the Hartree-Fock (HF) approximation for half-filled alternant systems are shown to be sensitive to correlations in the ground state of N≤12 Hubbard and PPP chains. Accurate N→∞ extrapolations are found for near neighbors. The correct ground-state charge density <np>=1 is a property of half-filled alternant systems and thus not a test of HF or other one-electron approximations. Spin correlations in PPP models with standard molecular parameters and long-range Coulomb interactions are approximately given by on-site interactions of U⋍ 2//t// in Hubbard models, although the general semiempirical PPP approach to conjugated molecules is preferable for wide-band systems.

Item Type:Article
Source:Copyright of this article belongs to The American Physical Society.
ID Code:39450
Deposited On:12 May 2011 14:21
Last Modified:12 May 2011 14:21

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