Optical Properties of Silver Bromide*†

The optical properties of silver bromide at room temperature have been determined in the energy range of 3–16 eV by means of reflectivity measurements. In the near-ultraviolet region (uv), the four absorption peaks reported by Okamoto were observed at 3.96, 4.40, 5.46, and 6.20 eV. The high-energy side of the largest peak at 6.20 eV decreased approximately 40% of its maximum before yielding to the vacuum-ultraviolet (vuv) spectrum consisting of well-defined peaks at 8.05, 10.1, and 12.3 eV. The reflectivity decreased quite rapidly for photon energies greater than 13.0 eV. A Kramers–Kronig analysis was employed to calculate the phase shift on reflection and the resulting optical constants. Vacuum-ultraviolet spectra of R, α, n, κ, ∊1, ∊2, and Im(1/∊) of silver bromide are given for the first time. Details of these measurements and calculations and discussion of alternative band-theoretical interpretations of the observed structure are given.