Effective electron-hole interaction potentials and the binding energies of exciton-ionized-donor complexes

Several recently proposed effective potentials for the electron-hole interaction in a polarizable medium are tested in the calculation of the binding energies of Wannier-exciton-ionized-donor complexes for CdS and ZnO crystals. The recent contention concerning unsuitability of the Haken potential for this problem is confirmed. None of the potentials investigated was found to be successful in both crystals. For CdS the potential proposed recently by Aldrich and Bajaj is able to yield good agreement with experiment. For ZnO the potential proposed by Pollmann and B\"uttner is found to be the best but the agreement with experiment is in general worse than for CdS. The possible causes of the discrepancies are pointed out, and treatments to account for these effects are suggested.