JDAM -- Jump Diffusion by Analytic Models

Abstract

Nanoscopic diffusion at surfaces normally takes place when an adsorbate jumps from one adsorption site to the other. Jump diffusion can be measured via quasi-elastic scattering experiments, and the results can often be interpreted in terms of analytic models. While the simplest model of jump diffusion only accounts for intercell jumps between nearest neighbours, recent works have highlighted that models which take into account both intracell and long-range intercell jumps are much needed. Here, we describe a program to compute the analytic lineshape expected from quasielastic scattering experiments, for translational jump diffusion on user-defined lattices. We provide an example of a general hexagonal surface composed of six sublattices, corresponding to the six principle adsorption sites - namely the top, two hollow, and three bridge sites. In that example we include only nearest-neighbour jumps. In addition, we provide a mean to calculate the lineshape for jumps on a hexagonal honeycomb lattice, with jumps up to the 10th nearest neighbour taken into consideration.