title: Highly compact wave functions for He-like systems.
abstract: Wave functions which are compact, but still quite accurate, are extremely valuable as tools for gaining understanding of quantum systems. This paper investigates the use for that purpose of functions that depend exponentially on all the interparticle distances of a few-body system, illustrated by a study of the ground electronic states of the He isoelectronic series (Z from 1 to 10). Using as few as 4 exponential basis functions, it is found that nonrelativistic energies are reproduced to within 38 microhartrees of the exact values, an error far less than for previously reported compact wave functions. Other properties are also well-represented.
authors.affiliation: Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA. harris@qtp.ufl.edu
authors.forename: Frank E
authors.initials: FE
authors.lastname: Harris
authors.forename: Vedene H
authors.initials: VH
authors.lastname: Smith