Experimental energy dispersions for valence and conduction bands of palladium

Using angle-resolved photoemission with synchrotron radiation, we have determined accurate energy-versus-momentum dispersion relations along the $〈111〉$ direction using a Pd(111) crystal. The energy E ({} 0.1 eV accuracy) and the momentum parallel to the surface →k_∥ are measured directly. The perpendicular component of the momentum k_⊥ is obtained from the measured final energy via a calculated free-electron-like final band that is found to be accurate within ±{}5% of the zone-boundary momentum by comparison with certain critical points that have been measured directly (L₁, Γ^'₂, and Γ₁₅). For the initial bands, we find the dispersions of the two d-like Λ₃ bands and of the sp-type Λ₁ band. Measured critical points (in eV) for bands numbered with increasing energy are: Γ2,3,4=-2.55±0.15, Γ5,6=-1.15±0.1, Γ₇=18.4±0.5, Γ₈=21.7±0.5, L₄=-0.4±0.2, L₅-0.1±0.1, and L₇=7.7±0.3. Spin-orbit splitting ({~} 0.4 eV maximum) is observed for the upper Λ₃ band.