Photoemission Studies of Platinum

Photoelectron energy-distribution curves of Pt at photon energies $6.8\le \hslash \omega \le 11.6$ eV exhibit structure originating from initial states 3.6, 2.5, 1.5, and between 0.7 and 0.2 eV below $E_F$. A strong peak at - 0.2 eV observed for $\hslash \omega <9.1\mathrm{}$ eV is joined by a second peak at - 0.7 eV in the range $\hslash \omega =9.1\mathrm{}-9.7$ eV. Above 9.7 eV, the two peaks merge to a single rounded peak at - 0.5 eV which grows stronger and sharper at higher photon energy. Good correspondence is found between structure in the energy-distribution curves and in a calculated band density of states. The results are discussed in terms of the direct and nondirect models of optical excitation and compared to similar results from Ni, Pd, and Rh.