Reflectivity of single-crystal GeS from 0.1 to 30 eV

The reflectivity of single-crystal, orthorhombic GeS has been measured at 300^∘{}K for all three polarizations in the photon energy range 0.1-30 eV. Eleven distinct peaks or shoulders are observed, about half of which can be associated with known structure in the valence-band density of states. A Kramers-Kronig analysis was performed, giving the optical constants and energy-loss functions in the 0-25-eV range.