The EPR speetra. of DCEL ZnS:Mu

Cu vary with the different cal cining temperature

T

. Simulating the EPR spectra with microcomputer

one can calculate the relative concentration

C

C

/C

of Mn

2+

clusters. As calcining temperature

T

grows over 950℃

the

C

C

/C

increases with

T

. We can conclude that formation of Mn

2+

clusters is relative to the structural phase. The sixfold lattice (α phase) enhances the spin exchange interaction of Mn

2+

ions and accelerates the formation of Mn

2+

clusters. The luminescence intensity

I

decreases with the increasing relative concentration

C

C

/C

of Mn

2+

clusters.The optimal calcining temperature of DCEL ZnS:Mn

Cu powder is discussed.