XAFS spectra from reflectivity measurements

The reflectivity of TiSi₂ films was measured as a function of photon energy E at the Ti K-edge region at a glancing angle θ close to the critical angle θ_C of total reflection. TiSi₂ silicide films (about 30 nm thickness) were prepared by silicidation of Ti thin films deposited on Si(001) substrates. Since the Fresnel reflectivity R(θ,E) is a function of the dispersion δ(E) and of the absorption β(E), the absorption β(E) which carries the XAFS signal can be solved as β(θ,δ,R) for observed reflectivity R and for estimated δ. The dispersion δ(E) is related to the absorption β(E) by the Kramers–Kronig (K–K) relations since the refractive index is n(E) = 1 − δ(E) − iβ(E). β(E) was calculated from the observed reflectivity R(θ,E) using theoretical values for initial δ(E). Titanium K-edge XAFS for TiSi₂ was extracted from the reflectivity by `ReflXAFS'.