Photoluminescence of single crystals and sintered slices of ZnS:Sm

3+

was investigated. Sm

3+

ions were introduced into samples by thermal diffusion. Three groups of lines

at 570nm

600nm and 650nm

were analyzed. They correspond to transitions of

4

F

5/2

-

6

F

5/2

4

F

5/2

-

6

F

7/2

and

4

F

5/2

-

2

H

9/2

respectively.In the emission spectra of

4

F

5/2

-

6

H

5/2

transition of Sm

3+

in ZnS(Fig.l) it was found that there were two groups of lines:lines 1

2 and 6 belonging to group It and lines 4 and 8 belonging to group I. The lines of group I keep the same relative intensities in different samples and the lines of group I also do so.From time resolved spectra it was found that the lines of the same groups had the same decay time.The lines of group I have decay time of 643us and group I has decay time of 475us (Fig.2). These two groups of lines also have different excitation spectra(Fig.3).The above experements prove that two groups of lines come from two different Luminescent centers

group I comes from center I and group II from center Ⅱ.