Path integral Monte Carlo simulations of the melting of molecular hydrogen surfaces |
| |
Authors: | Marcus Wagner David M Ceperley |
| |
Affiliation: | (1) Beckman Institute, National Center for Supercomputing Applications, USA;(2) Department of Physics, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave., 61801 Urbana, IL |
| |
Abstract: | We have used Path Integral Monte Carlo to study the surface melting of molecular hydrogen. Density profiles perpendicular and parallel to the bare H2 surface are computed showing the formation of a liquid adlayer at 6 K, less than half the bulk melting temperature of para-hydrogen, 13.8 K. To estimate the onset temperature and depth of H2 surface melting we determine the static structure factor within the individual H2-layers for wave vectors in the plane and find no crystalline order down to 3 K in a partially filled H2 adlayer at the free surface. We find quantum effects amplify the melting point depression at the free H2 surface compared to bulk by a factor of five over classical Lennard-Jones solids and find that the zero-point fluctuations of molecules at the surface are much enhanced over their bulk values. We see vacancy formation in the solid before melting. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|