The emission and excitation spectra of the SrS: Pb
2+ and SrSe: Pb
2+ phosphors were measured at low temperatures. The
3A1u→
1A1g emission band at 374 or 392 nm is observed at 80 K in addition to the
3T1u→
1A1g emission band at 368 or 383 nm for SrS: Pb
2+ or SrSe: Pb
2+, respectively. On these emission bands, phonon structures appear at 6 K. The zero-phonon line on the
3A1u→
1A1g emission band grows under the external magnetic field. The sharp excitation band observed at 351 nm for SrS: Pb
2+ or at 368 nm for SrSe: Pb
2+ at 80 K is assigned to the
A band in the isolated Pb
2+ center. The excitation mechanism in the high energy region is explained as the transfer of the excitation energy from the host crystal to an unexcited Pb
2+ ion. It is confirmed that the rigid rotator model which explains admixture between the
3T1u and
3A1u states is also available for the complex Pb
2+(S
2−)
6 or Pb
2+(Se
2−)
6 in these phosphors.
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