Independent assessments of the accuracy of correlated wave functions for many-electron systems

Abstract

The assessment of the accuracy of fully correlated wavefunctions by means of variance methods requires computation which only varies as N³, a lower power of N, the number of electrons, than had been expected. This seems to be dependent on an indirect approach first constructed for a transcorrelated method. This means that various different variance tests could be used for the assessment of the accuracy of wavefuctions calculated by the transcorrelated method developed by Handy and Boys. These would require much less equipment in programmes and computer facilities, than the original calculations of such wavefunctions. Supplementary investigations on correlated wave-functions at this level might make possible a whole variety of informative experiments on very exact wavefunctions and energies.