Anthony D. Novaco

Two-dimensional evaporation and substrate heterogeneity effects in submonolayer helium films

A model calculation is used to argue that the low-temperature, low-coverage specific heat of submonolayer4He films is evidence for the evaporation of a two-dimensional, liquid ground state. The smearing effect of small substrate inhomogeneities is demonstrated, and the effects of the thermal excitation of the liquid state are estimated. Arguments as to why these effects are not present in3He films are given.

The Adsorbed Helium Film: Two Dimensionality Versus Reality

The lesson of monolayer physics is certainly the usefulness of two-dimensional models in the understanding and interpretation of experimental results.1 This is especially true for those systems using graphite-like substrates and, in particular, those systems in which helium is the adsorbed species. The two-dimensional nature of adsorption on the graphite-like substrates is due to both the strong interaction of gases with these solids, and the fact that the surfaces of these substrates are unusually clean and nearly ideal.2,3