T. Thorsteinsson and D. L. Cooper.
In: “Quantum Systems in Chemistry and Physics. Volume 1: Basic problems and models systems” ed. A. Hernández-Laguna, J. Maruani, R. McWeeny and S. Wilson (Kluwer, Dordrecht); 303-26 (2000).

Abstract

We discuss all of the key features of our current CASVB methodology for modern valence bond calculations on ground and excited states. The CASVB strategy may be used to generate compact representations of CASSCF wavefucnctions or, alternatively, to perform the fully-variational optimization of various general types of VB wavefunction. We report also a new application, namely to the fourteen pi electrons of a planar dimethylenecyclobutadiene chain with three rings.

Key words: CASVB; modern valence bond; spin-coupled theory; CASSCF; VB.