A Computational Algorithm to Produce Virtual X-ray and Electron Diffraction Patterns from Atomistic Simulations

Simulation of kinematic Kikuchi diffraction patterns from atomistic structures

“…The method is derived from the virtual diffraction algorithm developed by Coleman et al [1] , [2] , which computes diffraction intensities across a three-dimensional mesh of reciprocal lattice points (RELP), each described by a wave vector K . The wave vector K represents the difference between the incident and diffracted wave vectors for radiation passing through a sample [3] .…”

SLADS: a parallel code for direct simulations of scattering of large anisotropic dense nanoparticle systems

“…In SLADS, both X-ray and electron scattering are available. The scattering intensity per atom, I, for a system consisting of N atoms, is computed as the product of the structure factor FðqÞ with its complex conjugate, F Ã ðqÞ (Coleman et al, 2014;Warren, 1969):…”

“…To sample q points on an Ewald sphere, one way is to generate a three-dimensional grid in reciprocal space (Coleman et al, 2014) and then search within this grid for those q points intersecting with the Ewald sphere of radius 2=. Alternatively, we can divide a circle on the Ewald sphere for a given computer programs 2 into fine segments at an angle increment of d'; each segment corresponds to a specific q point ( Fig.…”

Performance Improvement and Workflow Development of Virtual Diffraction Calculations

“…The mesh of reciprocal space points is built on a rectilinear grid with resolution defined by the user [16,17]. By constructing a high-resolution reciprocal space mesh, strong intensity peaks associated with the constructive interference between the incoming x-ray or electron beam and the crystal lattice are intuitively captured without a priori knowledge of the crystal structure of the material.…”

“…Following a concise discussion of the computational algorithm, this article presents advancements made to increase performance and scalability, and the integration of this algorithm into a workflow across heterogeneous computing hardware including visualization. A complete discussion of the virtual diffraction algorithm is provided in [16,17] along with application of this method to study grain boundary structure, nanocrystalline materials and interfaces between complex solids.…”