| In this dissertation I report the results of thermodynamic measurements performed on Neon (Ne) films adsorbed on HiPCo(TM) single-walled, closed-end, purified carbon nanotube bundles. The heat capacity was measured for 17 coverages between 0.015 and 1.2 single atomic layers, for 1.8 K < T < 19 K. A few complementary adsorption isotherms were measured on the same cell over a similar range of coverages, for 17.8 K < T < 27.9 K. The results indicate that Ne deposits, in order, in high binding energy sites, the grooves on the outside of the bundles, the surface of the outer nanotubes, and after compressing the fully completed monolayer, on a second layer. All of the films show solid-like behavior in the range studied. For the lowest coverages, possible excitation energies and Debye temperatures from a one dimensional model have been estimated. For the higher coverage films, I have calculated two-dimensional Debye temperatures and compared to results obtained on Ne adsorbed on flat graphite (Grafoil(TM)). The 2d isothermal compressibility of the films near monolayer completion has been estimated from vapor pressure isotherms at 19.2 K. Agreement is found between the monolayer completion coverage inferred from the heat capacity isotherms and a minimum in the compressibility. In spite of the solid-like behavior and similarities to Ne/graphite, I do not observe any phase transition in the range of temperatures and coverages studied, analogous to the sublimation, melting and vaporization transitions of Ne in two dimensions. |
