Impurity dynamics of boson liquid films

The dynamic properties of ³He impurity atoms in ⁴He films are calculated using a dynamic, microscopic variational theory. Our results for the binding energies, excitations energies, and effective masses on strong substrates agree well with experimental data of the Amherst group. No substrate bound states are found for substrates as weak as Na. The theory also provides an unambiguous description of atom scattering and sticking. The dependence of the sticking and scattering coefficients on the substrate and the excitations in the film have been calculated.