The joint use of metastable deexcitation spectroscopy and angle resolved ultraviolet photoemission gives a valuable contribution to the comprehension of the physical-chemical reactions occurring during the formation of an interface between different materials. This approach has been applied to study the evolution of the surface valence band of CaF, deposited on Si(001) at different temperatures. Under suitable growth conditions, CaF2 nanostructures of different shape and size can be obtained. Information regarding the chemical reactions taking place within the first deposited layer and the dependence of the electronic properties on film thickness was derived. (C) 2002 Elsevier Science B.V. All rights reserved.