Is Auger-free luminescence present in CeF3?

It is well known that Auger-free luminescence (AFL) is observable when the condition Eg>EVC is satisfied, where Eg is the band-gap energy between the lowest unoccupied band and the highest occupied band and EVC the energy difference between the top of the highest occupied band and the top of the next lower occupied band. From measurements of reflection and X-ray photoelectron spectra, CeF3 is demonstrated to really satisfy this condition. No evidence for AFL is found, nevertheless. The absence of AFL in CeF3 is related to a characteristic nature of its highest and next lower occupied bands, which are quite different from those of previously studied AFL-materials.