The energy distribution curve of the valence of a TiC single crystal was measured by x-ray photoelectron spectroscopy (XPS). The XPS measurement supports the augmented plane wave (APW) calculation after Ern and Switendick rather than the semi-self-consistent APW calculation after Conklin and Silversmith. The present modified APW calculation based on the neutral-atomic-charge densities was in good agreement with the XPS measurement. Moreover, the calculation was consistent with such available experimental data as x-ray emission and absorption spectra, optical reflectivity, and low-temperature specific heat. The peak (I) arising from the C $2s$ state is isolated from the valence-band peak (II) attributed to the C $2p$, Ti $3d$, and $4s$ states. The experimental intergrated intensity ratio of peak II to peak I is 2.9 to 1.0 which is nearly equal to the theoretical value 3 to 1. The calculated density of states at the Fermi level is 0.22 electrons/(eV primitive cell), which is nearly equal to the value of 0.23 from the electronic specific heat.

• Received 14 August 1974

DOI:https://doi.org/10.1103/PhysRevB.12.5465