Separation dynamics of luminescence from Raman scattering in characteristic X-ray radiation processes of Y compounds

We theoretically study the separation dynamics of a luminescence from Raman scatterings in the spectrum of the X-ray radiation occurring by an electro nic transition from a shallow core level to a deep one in insulating solids of Y compounds. We consider a many-body problem in a four-band model compo sed of dispersionless deep and shallow core bands, and conduction and valen ce bands. The Coulomb interactions among the conduction electrons and the v alence holes are taken into account by the lowest-order perturbation theory . With this model, it is clearly shown that the radiation spectra have thre e components; a luminescence part and two Raman scattering parts. This resu lt agrees with the recent experiments of YF3, and YCl3,. We also show the o rigin of the three components cannot be explained by a one-body picture. (C ) 2001 Elsevier Science B.V; All rights reserved.