This graph shows the theoretical valence-band structure of rocksalt phase cadmium oxide in the lower portion of the figure with the high symmetry points indicated [1]. The density of states of the valence bands is shown as a projection onto the energy scale of the upper portion of the figure (shaded grey). The blue circles show an x-ray photoemission spectrum of the valence band region of single crystal CdO [2]. The black line shows a Gaussian broadened plot of the density of states, accounting for the XPS instrumental resolution, offset to match the zero-energy reference of the experimental data [3].

References:
[1] A. Schleife, F. Fuchs, J. Furthmüller, and F. Bechstedt. First- principles study of ground- and excited-state properties of MgO, ZnO, and CdO polymorphs. Phys. Rev. B, 73 (2006) 245212.
[2] Details of growth: J. Zuñiga-Pérez, C. Munuera, C. Ocal and V. Muñoz-Sanjosé. Structural analysis of CdO layers grown on r-plane sapphire (01-12) by metalorganic vapor-phase epitaxy J. Cryst. Growth 271 (2004) 233.
[3] P. H. Jefferson, T. D. Veal, P. D. X. King, C. F. McConville et al. (in preparation for submission to Phys. Rev. B)

Submitted by P.H. Jefferson, Department of Physics, University of Warwick, UK.