Optical Properties of Antimony and Bismuth in the Far Ultraviolet

We have measured the reflectance of antimony and bismuth films at various angles of incidence, for photon energies between 10 and 26 eV. Reflectance values have been used to calculate the optical constants n and k, which in turn yield ∊1 and ∊2 as well as the real and imaginary parts of ∊−1. For antimony, the ∊−1 function can be closely fitted with the inverted Drude–Sellmeier formula. The center of the resonance is at 16.0 eV, with a half-width of 5.2 eV, corresponding to a decay time of 1.2 × 10−16 sec. The bismuth data cannot be fitted with a simple Drude–Sellmeier model, but it is in good qualitative agreement with the known electron-energy absorption properties.