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PSSP , a computer program for the crystal structure solution of molecular materials from X‐ray powder diffraction data
Author(s) -
Pagola Silvina,
Stephens Peter W.
Publication year - 2010
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889810005509
Subject(s) - simulated annealing , diffraction , computer program , powder diffraction , x ray crystallography , crystal structure , crystallography , molecule , resolution (logic) , x ray , work (physics) , chemistry , computational physics , materials science , algorithm , physics , computer science , thermodynamics , optics , organic chemistry , artificial intelligence , operating system
This work describes the computer program PSSP (powder structure solution program) for the crystal structure solution of molecular solids from X‐ray powder diffraction data. This direct‐space structure solution program uses the simulated annealing global optimization algorithm to minimize the difference between integrated intensities calculated from trial models and those extracted in a Le Bail fit of the experimental pattern, using a cost function for dealing with peak overlap through defined intensity correlation coefficients, computationally faster to calculate than R wp . The methodology outlined is applicable to organic solids composed of moderately complex rigid and flexible molecules, using diffraction data up to relatively low resolution. PSSP performance tests using 11 molecular solids with six to 20 degrees of freedom are analyzed.