Abstract:
Spectroscopic and thermoactivation methods were used to study the processes of accumulation of electron and hole trapping centers and energy transfer of electronic excitations to impurities
in CaSO4
-Mn and BaSO4
-Mn. It is shown that electronic trapping centers are created during the
excitation of an anionic complex as a result of charge transfer from O2− → SO2−
4
to closely spaced
anionic complexes SO2−
4
in CaSO4 and BaSO4
. In CaSO4 and BaSO4
, energy transfer from the host to
impurities occurs at the moment of charge transfer from the excited anionic complex to the combined
radiative electronic state at 2.95–3.1 eV. This combined state is formed from electronic trapping centers
Mn+-SO−
4
and SO3−
4
-SO−
4
. It was found that the emerging combined radiative states at 2.95–3.1 eV
of sulfates, which are formed as a result of charge transfer from the excited anionic complexes to
the excited state of impurities, Tl+, Cu+, and Mn2+, occupy the same energy levels as the intrinsic
electronic trapping center SO3−
4
of the host at 2.95–3.17 eV. Experimental results show that during
UV photon irradiation, anionic complexes are excited mainly near impurities in sulfates.
