New variational wave function for liquid He3

Variational calculations, with a new wave function based on the Feynman-Cohen correlation operator, are carried out for liquid He3 with a Lennard-Jones potential. The wave function contains three-body correlations and momentum-dependent two-body correlations, in addition to the Jastrow correlations commonly used in variational calculations. The Fermi hypernetted-chain summation methods are generalized to calculate energy expectation values wiith this wave function. The calculated equilibrium energy and density are -2.±0.1 and 0.28±0.01σ-3, a significant improvement over the -1.25 and 0.22σ-3 obtained with the Jastrow wave function, and closer to the experimental -2.56a°K and 0.28σ-3.