Melting of a p-H2 monolayer on a lithium substrate -: art. no. 125405

Adsorption of p-H-2 films on alkali metals substrates at low temperature is studied theoretically by means of path integral Monte Carlo simulations. Realistic potentials are utilized to model the interaction between two p-H-2 molecules, as well as between a p-H-2 molecule and the substrate, assumed smooth. Results show that adsorption of p-H-2 on a lithium substrate, the most attractive among the alkali, occurs through completion of successive solid adlayers. Each layer has a two-dimensional density theta(e)approximate to0.070 A(-2). A solid p-H-2 monolayer displays a higher degree of confinement, in the direction perpendicular to the substrate, than a monolayer helium film, and has a melting temperature of about 6.5 K. The other alkali substrates are not attractive enough to be wetted by H-2 at low temperature. No evidence of a possible superfluid phase of p-H-2 is seen in these systems.