Vacuum-ultraviolet optical properties of single-crystal cadmium

The reflectivity of single-crystal Cd has been measured between 350 and 2500 \AA{} using synchrotron radiation. The data have been Kramers-Kronig analyzed and corrections for an overlayer of CdO discussed. The imaginary part of the dielectric constant exhibits a sharp rise at about 9.35 eV due to the onset of transitions from the top of the $4d$ bands to the Fermi level. These transitions persist, with structure, to high energy, only about a third of their oscillator strength being used by 30 eV. The bulk and surface plasmon energies are found to be 8.80 and 7.30 eV.