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We have applied the pseudopotential theory to the calculation of exciton states and binding energies for the ionic crystals CaF2, SrF2, and BaF2, using a transfer model. Because of the satisfying agreement between our results and the experimental data in each case, we assume this pseudopotential formalism will describe transfer exciton states and energies in other ionic crystals.Starostin 1 showed that the band structure for CaF 2 (and analogously for SrF2, BaF2) has the form of Fig. 1. Hermanson and Phillips 2,a developed a pseudo-potential formalism to describe exciton states with a total wave vector K = 0. Using their nomenclature (which is in agreement with Knox's 4) we obtain for the Hamiltonian of the crystal, neglecting all magnetic and relativistic terms: H=~,gh_~M. h2 ~ ZiZ~e 2 Z,e" e' 9 IRi-ril Jri~

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