Abstract
We have measured the Raman spectra of AgBr and AgCl in both the high-temperature solid and the melt. The melt spectra are strikingly similar to the spectrum of the superionic conductor αAgI. We have found that second-order Raman scattering from short-wavelength vibrations ("zone-boundary" phonons) is the primary scattering mechanism for the melts. The αAgI spectrum coincides with the silver-halide melt spectra when frequency is scaled by inverse square root of the halide mass ratio. We believe that the αAgI spectrum is also due mainly to the second-order processes and is affected by the molten cation sublattice. We find no evidence for a direct connection between the cation motion in αAgI and the Raman spectrum.