We present a calculation of the third sound speed c3 of thin4He films adsorbed on H2, Li, Mg, graphite and H2-plated graphite. The results show a clear correlation of oscillations in c3, with a period of one atomic layer, with the layering phenomena observed in adsorption isotherms. Comparison is made with recent experimental results for helium films on solid H2 by Shirron and Mochel and by Brisson, Mester and Silvera. The theoretical analysis suggests explanations for disagreements between different interpretations of data. A standard way of determining the number of so-called inert layers is questioned. Other available experimental data on graphite and H2-plated graphite are also discussed.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics