Non‐Periodic Local Motion of Silver Ions in β‐Ag3SI

The electrical conductivity of pressed pellets of β‐Ag3SI has been measured at frequencies from 107 Hz to 1013 Hz, at 295 K. Below 2 · 109 Hz the conductivity is found to be constant. At higher frequencies it increases, attaining a v2 frequency dependence at about 4 · 1010 Hz and eventually displaying a broad maximum centred at ca. 6 · 1011 Hz. Above 1012 Hz we observe the excitation of transverse optical phonons. ‐ In the 1010 Hz to 1010 Hz frequency regime the experimental conductivity is compared with conductivity spectra calculated on the basis of the following simple single‐particle models: (I) Brownian motion in a two‐dimensional harmonic potential, (ii) a microscopically reversible version of a two‐dimensional type of localized diffusion. In either treatment. the local motion turns out to be non‐periodic.