[Ifeffit] d-band vacancies vs d-band center

Hi All: I am wondering whether there is a specific correlation between d-band vacancies vs d-band center of Pt. We can acquire experimental d-band vacancies of Pt by XAFS from Pt LIII & LII XANES. I assume the downshift of d-band relative to Fermi level (lower d-band center) caused by for example alloying with the second metal will reduce the d-band vacancies since the part above Fermi level gets reduced. But it seems like it is not always true. I appreciate if someone can explain the correlation between these two or give relevant references. Regards, Jias