ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
All-electron partitioning of wavefunctions into products ΨcoreΨval of core and valence parts in orbital space results in the loss of core-valence antisymmetry, uncorrelation of motion of core and valence electrons, and core–valence overlap. These effects are studied with the variational Monte Carlo method using appropriately designed wavefunctions for the first-row atoms and cations. It is shown that the loss of antisymmetry with respect to an interchange of core and valence electrons is a dominant effect which increases rapidly through the row, while the effect of decorrelating the core and valence electrons is significantly smaller. Orthogonality of the core and valence parts partially substitutes the exclusion principle and is absolutely necessary for meaningful calculations with partitioned wavefunctions. Core–valence overlap may lead to nonsensical values of the total energy. Even relatively crude core–valence partitioned wavefunctions generally can estimate ionization potentials and electron affinities with better accuracy than that of the traditional, non-partitioned ones, provided that they achieve maximum separation (independence) of core and valence shells accompanied by high internal flexibility of Ψcore and Ψval. Our best core–valence partitioned wavefunction of that kind estimates the ionization potentials with an accuracy comparable to the most accurate theoretical determinations in the literature. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.475675
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