Compton profiles of FeTi andβ-phase FeTi hydride

The Compton profiles of polycrystalline FeTi and FeTi hydride in the $\beta$ phase have been measured by means of 320-keV photons from a ${}_{}{}^{51}{}_{}{}^{}\mathrm{Cr}$ source. The results have been corrected for multiple scattering and for the finite energy resolution of the spectrometer. The data are analyzed in terms of a renormalized-free-atom model. For FeTi, the best agreement between theory and experiment is obtained for a configuration $\mathrm{Fe}3d^{6}4s^2-\mathrm{Ti}3d^{2}4s^2$. The most characteristic feature of the $\beta$-phase hydride are antibonding hybrids of the electron wave functions of neighboring hydrogen atoms. A rigid-band-like behavior of the hydrogen electrons can be ruled out. The heat of solution of the $\beta$-phase hydride calculated from the Compton profile is in reasonable agreement with the experimental value.