Low-energy interband absorption in Pd

The optical absorptivity of crystalline Pd was measured at 4.2 K between 0.15 and 4.4 eV. The data were Kramers-Kronig analyzed to determine the dielectric functions and the optical conductivity, $\sigma$. A strong maximum was observed in $\sigma$ at 0.46 eV followed by a broad shoulder near 1.25 eV. These are interpreted in terms of transitions involving the bands near $L$ in the Brillouin zone.