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Photoemission measurements have been made of the intermetallic compound Pd 2 TiAl utilizing synchrotron radiation in the energy range 40-180 eV. The valence band extends to a binding energy of 7 eV. Measurements made at the Cooper minimum for Pd 4d indicate that the highest density of states for Ti 3d is at the Fermi edge and that it decreases towards higher energy. Using this density of states and correcting for the photoemission cross-sections with energy, it has been possible to determine the density of states for Pd 4d which also contributes to the Fermi level. Resonance photoemission measurements are consistent with this conclusion and also indicate that the Pd 4d band is not completely full.

Ultraviolet photoemission spectroscopy has been employed to provide information on the valence band of the Heusler alloy. The contribution of the d bands of Mn and Cu to the density of states has been investigated by means of 3p to 3d resonant enhancement. The valence band extends to 6 eV below the Fermi level, with a main peak at a binding energy of 3.2 eV and a shoulder extending to the Fermi edge. Resonant photoemission indicates that the Mn 3d character extends across the full width of the band. An experimental photoemission spectrum obtained at a photon energy of 40 eV has been compared with a calculated spectrum derived from a theoretical band structure. The main difference occurs in the region 1 - 2 eV below the Fermi level. The calculated spectrum exhibits a peak at a binding energy of 1.5 eV, comprising contributions from both the Cu and Mn 3d bands. There is no evidence of a similar feature in the experimental spectrum.

The valence bands of the intermetallic compounds Pd 2 TiIn and Pd 2 TiSn have been investigated by ultraviolet photoemission utilizing synchrotron radiation. The valence bands of both alloys have a width of 7-8 eV with a prominent peak at a binding energy of 2.6 eV and a shoulder extending to the Fermi edge. Measurements obtained at the Pd 4d Cooper minimum and at the Ti 3p threshold indicate that the feature at 2.6 eV is largely composed of contributions from Pd 4d states, whereas the Ti 3d states contribute most strongly immediately below the Fermi level. Experimental photoemission spectra show good agreement with theoretical calculations.

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