Variational calculations of liquidHe4with free surfaces

Results of variational calculations of the surface profile and energy of the free surface of liquid helium are presented. The trial wave function is taken to be a product of two-body Jastrow factors and one-body factors. We performed the numerical computations using Monte Carlo techniques. The obtained suface energy is 0.21°K/${\mathrm{\AA }}^2$ compared with the experimental value of 0.27°K/${\mathrm{\AA }}^2$. The density profile is found to have a very weak layered structure near the free surface. A scheme is proposed and carried out to test the consistency of other approximate microscopic calculations of the surface profile and energy. We also suggest that experiments be considered to probe the surface structure.