A semiempirical potential form is used to study the dynamics of a proton along an optical channel of a quartz sample containing an aluminum defect. The transit-time concept approach with an effective mass for the proton allows the proton diffusion to be determined. The exhausting source model, which simply describes the diffusion of the alkali-metal ions and their compensation by protons in the vicinity of the Al traps, gives a satisfactory interpretation of the observed ionic currents during electrodiffusion of quartz and can explain the behavior of these currents at short and long times.

• Received 11 December 1987

DOI:https://doi.org/10.1103/PhysRevB.38.5648