Excess-electron surface states of helium clusters

Abstract

Bound states of an excess electron attached to the surface of helium clusters $^{4}\mathrm{He}_{n}$ and liquid helium are calculated. The binding energy increases smoothly from 0.04 ${\mathrm{cm}}^{\ensuremath{-}1}$ for $n=5\ifmmode\times\else\texttimes\fi{}{10}^{5} \mathrm{to} 5.57$ ${\mathrm{cm}}^{\ensuremath{-}1}$ for bulk liquid helium. The splittings of the first two excited states of the excess electron on a liquid-helium surface are reproduced to within 1% of the experimental values. We expect similar accuracies for the cluster states.