Surface-State Lifetimes and Current Flow in Liquid Helium

The lifetime of electrons trapped at the free surface of liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ has been determined from the temperature dependence of the current flow in the liquid. These lifetimes are in substantial agreement with the values determined directly for the liquid-gas interface in ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. New results are presented for the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$-${}_{}{}^3{}_{}{}^{}\mathrm{He}$ interface which give lifetimes as long as ${10}^5$ sec.