MOBILITY OF POSITIVE-IONS IN BULK LIQUID-HELIUM

It is shown that the roton-limited mobility varies with temperature as <(sigma)over bar>(r)e(-Delta/kBT) where <(sigma)over bar>(r) is the r oton scattering cross-section and a is the roton minimum. The theoreti cal phonon-and roton-limited mobilities are in good agreement with the experimental data for the temperature ranges from similar to 0.02 K t o similar to 0.12 K and from similar to 1.0 K-1 to similar to 1.85 K-1 , respectively.