Stochastic and Deterministic Crystal Structure Solution Methods in GSASII: Monte Carlo/Simulated Annealing Versus Charge Flipping
Abstract
One of the goals in developing GSASII was to expand from the capabilities of the original General Structure Analysis System (GSAS) which largely encompassed just structure refinement and post refinement analysis. GSASII has been written almost entirely in Python loaded with graphics, GUI and mathematical packages (matplotlib, pyOpenGL, wxpython, numpy and scipy). Thus, GSASII has a fully developed modern GUI as well as extensive graphical display of data and results. However, the structure and operation of Python has required new approaches to many of the algorithms used in crystal structure analysis. The extensions beyond GSAS include image calibration/integration as well as peak fitting and unit cell indexing for powder data which are precursors for structure solution. Structure solution within GSASII begins with either Pawley or LeBail extracted structure factors from powder data or those measured in a single crystal experiment. Both charge flipping and Monte CarloSimulated Annealing techniques are available; the former can be applied to (3+1) incommensurate structures as well as conventional 3D structures.
 Authors:
 Argonne National Lab. (ANL), Lemont, IL (United States)
 Publication Date:
 Research Org.:
 Argonne National Lab. (ANL), Argonne, IL (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC22)
 OSTI Identifier:
 1377892
 Grant/Contract Number:
 AC0206CH11357
 Resource Type:
 Journal Article: Accepted Manuscript
 Journal Name:
 Crystals
 Additional Journal Information:
 Journal Volume: 7; Journal Issue: 9; Journal ID: ISSN 20734352
 Publisher:
 MDPI
 Country of Publication:
 United States
 Language:
 English
 Subject:
 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; GSASII; Monte Carlo/Simulated Annealing; chaos mathematics; charge flipping; structure solution
Citation Formats
Von Dreele, Robert. Stochastic and Deterministic Crystal Structure Solution Methods in GSASII: Monte Carlo/Simulated Annealing Versus Charge Flipping. United States: N. p., 2017.
Web. doi:10.3390/cryst7090264.
Von Dreele, Robert. Stochastic and Deterministic Crystal Structure Solution Methods in GSASII: Monte Carlo/Simulated Annealing Versus Charge Flipping. United States. doi:10.3390/cryst7090264.
Von Dreele, Robert. 2017.
"Stochastic and Deterministic Crystal Structure Solution Methods in GSASII: Monte Carlo/Simulated Annealing Versus Charge Flipping". United States.
doi:10.3390/cryst7090264. https://www.osti.gov/servlets/purl/1377892.
@article{osti_1377892,
title = {Stochastic and Deterministic Crystal Structure Solution Methods in GSASII: Monte Carlo/Simulated Annealing Versus Charge Flipping},
author = {Von Dreele, Robert},
abstractNote = {One of the goals in developing GSASII was to expand from the capabilities of the original General Structure Analysis System (GSAS) which largely encompassed just structure refinement and post refinement analysis. GSASII has been written almost entirely in Python loaded with graphics, GUI and mathematical packages (matplotlib, pyOpenGL, wxpython, numpy and scipy). Thus, GSASII has a fully developed modern GUI as well as extensive graphical display of data and results. However, the structure and operation of Python has required new approaches to many of the algorithms used in crystal structure analysis. The extensions beyond GSAS include image calibration/integration as well as peak fitting and unit cell indexing for powder data which are precursors for structure solution. Structure solution within GSASII begins with either Pawley or LeBail extracted structure factors from powder data or those measured in a single crystal experiment. Both charge flipping and Monte CarloSimulated Annealing techniques are available; the former can be applied to (3+1) incommensurate structures as well as conventional 3D structures.},
doi = {10.3390/cryst7090264},
journal = {Crystals},
number = 9,
volume = 7,
place = {United States},
year = 2017,
month = 8
}

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