Theory of quasielastic neutron scattering by hydrogen in metals considering finite jump times

Abstract

A method is presented of calculating the quasielastic neutron scattering by hydrogen diffusing in metals, taking into consideration finite jump times τ 1, in contrast to earlier theories in which only the case of τ 1 being small compared to the mean residence time τ 0 had been treated. Compared to the case τ 1 = 0, finite jump times cause a considerable change in the shape and half-width of the scattering function. For τ 1/τ 0 ≈ 10 −1 with increasing jump time a broadening of the scattering function results. For τ 1/τ 0 ≈ 1 at certain values of the momentum transfer the central quasielastic peak disappears and side peaks occur which reflect the backward and forward jumping between two interstitial sites.