Electronic structure and luminescence mechanisms in MIMIII(MoO4)2 molybdates

The mechanisms of intrinsic luminescence in several molybdate crystals of M
^I
M
^III
(MoO
4
)
2
(M
^I
= Li, Na, K; M
^III
=Bi, Y, Fe) type are revealed in complex experimental and theoretical studies. The luminescence spectroscopy studies under VUV synchrotron excitations are applied together with the electronic structure calculations carried out by the FLAPW method. Simultaneous analysis of diffuse reflectance and luminescence excitation spectra is used for determination of the energy gap (Eg) values of the crystals. It is found that the molybdate groups MoO
4
2− play dominant role in the processes of intrinsic luminescence in studied molybdate compounds.