Path-Integral Calculation of the Two-Particle Slater Sum forHe4

Abstract

The Wiener integral formulation combined with Monte Carlo sampling has been used to compute the twoparticle Salter sum for ${\mathrm{He}}^4$ for temperatures ranging from 273°K down to 2°K, the lower practical limit for this computational method. This is equivalent to a calculation of the density-independent part of the pair distribution function. A Lennard-Jones 6-12 potential has been used to describe the interaction. Contributions from exchange were found negligible at 5°K and above. Comparisons with the Wigner-Kirkwood expansion are made. The second virial coefficients derived from these results are within two or three percent of the results obtained from the usual phase-shift calculation.