The line‐broadening effect of correlations between successive jumps of a Mo¨ssbauer atom is investigated. The ’’encounter model’’ originally developed for nuclear‐magnetic‐resonance diffusion studies is applied to describe temporal and spatial correlations which may cause significantly smaller linewidths than a random‐walk diffusion mechanism. This straightforward analytic generalization of the random‐walk results is capable of eliminating some of the earlier discrepancies between diffusion constants determined from radio‐tracer and Mo¨ssbauer experiments.