Location of holes in Y1-xPrxBa2Cu3O7

Recent experiments by Merz er al. [Phys. Rev. B 55, 9160 (1997)] demonstrated that the loss of superconductivity upon Pr doping is associated with the change of the character of the oxygen holes from p(sigma) to p(pi). This experiment sheds light onto the long-standing problem of T-c suppression by Pr, and helps to rule out a number of theoretical models, leaving only those which predict such a transfer of the O holes. To distinguish between the two models that do predict such an effect, one has to access the ratio of the planar and axial character of the holes. We do so in this paper.