An accurate and compact wave function for the 4He dimer
Dipartimento di Scienze Chimiche e Ambientali, Università dell'Insubria - Via Lucini 3, I-22100 Como, Italy, EU
Accepted: 25 August 2011
We introduce a local measure of the quality of a trial wave function: the local variance. Using this tool we examine the pair function often adopted to construct wave functions for small helium clusters and apply it to a wave function for 4He2 using the TTY interaction potential. Our analysis shows that this commonly employed functional form should be improved in the short-range region. We introduce a new model based on the short-range behaviour of the exact ground-state solution of a Morse potential. The resulting compact trial wave function for 4He2 recovers 98% of the exact binding energy with only six variational parameters.
PACS: 36.40.-c – Atomic and molecular clusters / 31.15.xt – Variational techniques
© EPLA, 2011