Cluster-Bethe-lattice treatment for theU2center in alkali halides

Abstract
A cluster-Bethe-lattice calculation for the electronic density of states of a U2 center in the rocksalt structure is presented for a simple one-orbital Hamiltonian. The parameters involved in the Hamiltonian are given values based on qualitative arguments for Na, K, Rb chlorides and bromides and the proton contact term is calculated for these sets of parameters, in fair agreement with experimental data.