The spectra and decay time of RbCaF3 emission at monochromatic X-ray e
xcitation have been measured, It is shown that the short wavelength fa
st (2.8 ns) intrinsic luminescence of the crystal consists of two band
s (245 and 285 nm), which confirms the model of radiative core-to-vale
nce transitions for perovskite structure crystals. A stepwise decrease
of the light yield near the K-edge adsorption of Rb (15.2 keV) is obs
erved. (C) 1997 Elsevier Science B.V.