The SPM calculated ZFSPs b D
 and theoretically by Rudowicz et al. ; and a couple of experimental ,  and  and theoretical  studies were carried out for K2ZnF4:Cu2+ system. Besides, numerous theoretical studies focused on some other systems K2ZnF4:Ni2+, K2ZnF4:Mn2+ and , and K2ZnF4:Co2+. On the other hand, for Cr3+ doped K2ZnF4, the experimental  and  and theoretical  and  studies were carried out so as to understand the local structure around the dopant Cr3+ ions.