Calculation of x-ray scattering patterns from nanocrystals at high x-ray intensity

Malik Muhammad Abdullah, Zoltan Jurek, Sang-Kil Son, and Robin Santra

[BibTeX][pdf]doi:10.1063/1.4958887

We present a generalized method to describe the x-ray scattering intensity of the Bragg spots in a diffraction pattern from nanocrystals exposed to intense x-ray pulses. Our method involves the subdivision of a crystal into smaller units. In order to calculate the dynamics within every unit, we employ a Monte-Carlo-molecular dynamics-ab-initio hybrid framework using real space periodic boundary conditions. By combining all the units, we simulate the diffraction pattern of a crystal larger than the transverse x-ray beam profile, a situation commonly encountered in femtosecond nanocrystallography experiments with focused x-ray free-electron laser radiation. Radiation damage is not spatially uniform and depends on the fluence associated with each specific region inside the crystal. To investigate the effects of uniform and non-uniform fluence distribution, we have used two different spatial beam profiles, Gaussian and flattop.

Tags: XATOM, XMDYN, XSINC, CFEL, DESY, x-ray scattering, x-ray diffraction, nanocrystal, molecular imaging