Accurate “doubly-occupied orbital sea” approximation for the many-electron valence bond wavefunction
✍ Scribed by Bernard Kirtman; Daniel M. Chipman
- Publisher
- Elsevier Science
- Year
- 1974
- Tongue
- English
- Weight
- 297 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
A new approximation method based on the dominance of intra-pair correlations is proposed for calculating manyelectron valence bond wavefunctions. This "doubly-occupied orbital sea" valence bond method (DOS VB) gives accurate orbit& as well as energies. l3e computation time increases with the number of electrons 2s I@ rather than (Ntl)! 2s for an exact calculation. Results for BH are presented by way of illustration. * 'Ihe overlaps reported here are with the Blint et al. [l] SOGI orbitals. They are slightly different from the perfect-pairing valence-bond values (which are expected to be even closer to unity). ** This is because of the introduction of pseudo-dissociative electron pairs with perturbed wavefunctions which are difficult to characterize using any discrete basis. For further discussion see refs. [4,5 1. *** This is not quite true since different methods for fitting the x's could be used. However. we feel that all reasonable criteria will yield pretty much the same results. The fmai orbitais do not depend noticeably upon the initial guess. t A simplified uncoupled "'distinguishable electron" method has been previously proposed. For the latter see ref.
[ 71.