Theory for the Ionization Potential of Clusters of Rare Gas Atoms

We present a theory for the ionization potential of clusters of rare gas atoms. It accounts for the polarization of the rare gas atoms and the delocalization of the hole. Results for the vertical ionization potential are obtained for very large cluster sizes. A comparison with experiments indicates that a gradual size‐dependent transition from adiabatic ionization (for small clusters) to vertical ionization (for bulk and large clusters) has been observed.