Formation of titanium fulleride studied by x-ray spectroscopies

The chemical interaction between titanium and C-60 in coevaporated titanium-fulleride films has been investigated by x-ray photoelectron spectroscopy, (XPS), x-ray absorption spectroscopy (XAS), and x-ray emission spectroscopy. Two titanium-fulleride films with different Ti concentrations (x = 2.1 and 3.6) and a pure C-60 film were chosen in this study. C 1 s XPS analyses show a binding-energy shift and a Line-broadening effect. C 1 s XAS study of Ti2.1C60 shows a small change of the pi* absorption resonance, with respect to its intensity and energy position, and a variation of the spectral shape in the sigma* absorption region in comparison with pure C-60 The C Ka x-ray emission spectra of the films show the same total emission bandwidth as pure C-60 For resonant and nonresonant excitations, an x-ray spectral profile similar to pure C-60 is observed from the Ti2.1C60 film, while the Ti3.6C60 film results in a spectral profile with some contribution from titanium carbide. All the experimental results indicate that a titanium-fulleride compound has been formed in the coevaporation process of C-60 and titanium. [S0163-1829(99)03119-7].