Calculation of the Photoelectric Emission from Tungsten, Tantalum, and Molybdenum

A calculation of the photoelectric emission due to direct transitions between volume states of the crystal is carried out for tungsten, tantalum, and molybdenum. The calculations include a determination of the energy band structure by the augmented-plane-wave method for each metal. The Fermi energies and density-of-states histograms are obtained. The matrix elements for direct interband transitions are calculated throughout the Brillouin zone, and are found to vary widely as a function of $k$. The resulting histograms for the photoelectric yield and typical energy-distribution curves are presented.