Kapitza conductance due to helium atoms interacting with a surface

Abstract

A calculation has been made of the Kapitza conductance between a solid and helium as a result of the interaction between independent helium atoms and the solid. In the low temperature limit the expression for the conductance due to transitions between unbound states is the same as that for phonon radiation into the gas, that is, the Khalatnikov model with appropriate minor modifications. At higher temperatures it increases above this limit suggesting that the neglect of the attractive potential is a significant defect of the Khalatnikov model. The conductance due to transitions between bound and unbound states has also been calculated. Because of the neglect of interactions between helium atoms the model only becomes realistic for this process at the higher temperatures when the conductance is less than that due to transitions between continuum states.