Wetting phenomena in films of molecufar hydrogen isotopes
نویسندگان
چکیده
" triple point wettings," and gave no indications for a prewetting transition in this range. At low temperatures (T<T, /3) h e equilibrium film thickness reaches only a few monolayers. Thicker films. prepared by quench-condensation of H2 gas at 1.5 K. undergo a dewetting process during annealing: most of the film material contracts to clusters. and in between the films thin down to its equilibrium zhickness. This surface diffusion process is thermally activated, with an activation energy of 23 K (in h e case of HJ. The dewetting kinetics have not revealed any indication for a surface-molten layer on the solid films at low temperatures, or for a superfluid component. O I996 American Iwirure of Physics. [S 1063-777X(96)0050211
منابع مشابه
On dewetting dynamics of solid films of hydrogen isotopes and its influence on tritium spectroscopy
The dewetting dynamics of solid films of hydrogen isotopes, quench-condensed on a graphite substrate, was measured at various temperatures below desorption by observing the stray light from the film. A schematic model describing the dewetting process by surface diffusion is presented, which agrees qualitatively with our data. The activation energies of different hydrogen isotopes for surface di...
متن کاملTriple-point wetting of molecular hydrogen isotopes
Triple-point wetting is a well-known phenomenon of simple adsorbates on solid substrates, which involves, in the liquid phase above the triple-point temperature, T3, complete wetting with the formation of arbitrary thick films being observed, whereas below T3 only a few monolayers of the solid phase are adsorbed at saturated vapour pressure. This effect is usually ascribed to the substrate-indu...
متن کاملCritical Phenomena at Interfaces Phase Transitions at Quantum Surfaces
Tlre qnantum systems helium and hydrogen provide a versatile testing ground for studying interfacial phenomena. As examples, both some properties of surface< near thermodynamic equilibrium, like layering and wetting, and uonequilibrium states of qucnch-condensed disordered films are discussed. A further topic is the development of macroscopic instabilities of interfaces under external perturbat...
متن کاملTriple-point wetting on rough substrates.
The influence of substrate roughness on the wetting scenario of adsorbed van der Waals films is investigated by theory and experiment. Calculating the bending free energy penalty of a solid sheet picking up the substrate roughness, we show that a finite roughness always leads to triple-point wetting reducing the widths of the adsorbed solid films considerably as compared to that of smooth subst...
متن کامل