Negative ions at an interface between liquid helium mixtures

Abstract

The properties of electron bubbles electrostatically forced against an interface between liquid 3He and saturated 4He–3He mixture were determined at low temperatures. The equilibrium state of such objects is characterized by the binding energy of 6.5 K and oscillatory spectrum of first excitations with a frequency of 0.6·1010 s–1. The shifting electric field E = 100 V/cm at the temperature T = 0.2 K leads to decaying the bound bubble state with the lifetime τ ≈ 1 s. The experimental study of bubble electron states can appear to be useful for determining properties of an interface between liquid helium mixtures.