Optical absorption of hcp yttrium

The reflectivity of oriented, single-crystal, hcp yttrium was studied in this work between 3.5 and 30 eV. The data were combined with previous absorption measurements at higher and lower energies to enable the dielectric functions to be determined by Kramers-Kronig analysis. Optical anisotropy was shown to occur mainly below 4 eV. The structure in ${\epsilon }_2$ below 25 eV was interpreted in terms of solid state, interband features. The Y results were compared to earlier results for Zr and Hf. The loss functions were calculated from the dielectric functions, and Y was shown to possess two pairs of surface and volume plasmons.