#### Abstract

Variational Monte Carlo calculations of the ground states of drops containing 8*–*728 atoms of ${}_{}{}^{4}{}_{}{}^{}\mathrm{He}$ and 20*–*240 atoms of ${}_{}{}^{3}{}_{}{}^{}\mathrm{He}$ have been made. The variational wave functions include two- and three-body correlations and (for the Fermi drops) Feynman-Cohen backflow. We discuss the wave functions, their relation to modern variational wave functions for liquid ${}_{}{}^{4}{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^{3}{}_{}{}^{}\mathrm{He}$, the calculational techniques, and the results for the ground-state energies and density profiles. Our calculations indicate that ${}_{}{}^{3}{}_{}{}^{}\mathrm{He}$ drops with more than 40 atoms are bound, while a drop with 20 atoms is in a metastable state that has positive energy but negative chemical potential. The surface tensions of both liquid ${}_{}{}^{4}{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^{3}{}_{}{}^{}\mathrm{He}$ are obtained by liquid-drop fits to the calculated binding energies. From the density profiles of the largest drops we estimate the surface thickness of liquid ${}_{}{}^{4}{}_{}{}^{}\mathrm{He}$ to be 7 A*̊* while that for liquid ${}_{}{}^{3}{}_{}{}^{}\mathrm{He}$ is 8 A*̊*.

DOI: http://dx.doi.org/10.1103/PhysRevB.34.4571

- Received 13 March 1986
- Published in the issue dated 1 October 1986

© 1986 The American Physical Society