scholarly journals Stochastic and Deterministic Crystal Structure Solution Methods in GSAS-II: Monte Carlo/Simulated Annealing Versus Charge Flipping

Crystals ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 264
Author(s):  
Robert Von Dreele
Keyword(s):  
Crystal Structure ◽  
Monte Carlo ◽  
Simulated Annealing ◽  
Structure Solution ◽  
Solution Methods ◽  
Monte Carlo Simulated Annealing

Bridging the gap – structure determination of the red polymorph of tetrahexylsexithiophene by Monte Carlo simulated annealing, first-principles DFT calculations and Rietveld refinement

2002 ◽  
Vol 35 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Marcus A. Neumann ◽  
Consiglia Tedesco ◽  
Silvia Destri ◽  
Dino R. Ferro ◽  
William Porzio
Keyword(s):  
Crystal Structure ◽  
Monte Carlo ◽  
Simulated Annealing ◽  
Dft Calculations ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
First Principles ◽  
Density Functional ◽  
Space Groups ◽  
Monte Carlo Simulated Annealing

The crystal structure of the red polymorph of tetrahexylsexithiophene (THST) is solved from X-ray powder diffraction data by a direct-space Monte Carlo simulated-annealing approach. First-principles density functional theory (DFT) calculations are used to distinguish between three nearly identical solutions in the space groupsC2/m,C2 andP\bar{1} and to improve the overall accuracy of the crystal structure. The correct space group is found to beC2/m. In all space groups, the thiophene backbone is planar and the hexyl side chains assume an all-transconformation except for two terminal methyl residues, which adopt agaucheorientation. The ability of first-principles DFT calculations to provide atomic coordinates of single-crystal quality is demonstrated by lattice-energy minimization of the known crystal structure of the yellow polymorph of THST. The combination of Monte Carlo simulated annealing, first-principles DFT calculations and Rietveld refinement presented in this paper is generally applicable. It provides a powerful alternative to standard approaches in cases where the information content of the powder diffraction pattern alone is insufficient to distinguish between different structure solutions. DFT calculations can also provide invaluable guidance in Rietveld refinement.

scholarly journals Alpha-helix folding of human parathyroid hormone fragment by Monte Carlo simulated annealing

2000 ◽  
Vol 40 (supplement) ◽  
pp. S18
Author(s):  
Y. Okuda ◽  
M. Masuya ◽  
A. Mitsutake ◽  
Y. Okamoto ◽  
T. Nakazawa
Keyword(s):  
Monte Carlo ◽  
Simulated Annealing ◽  
Parathyroid Hormone ◽  
Alpha Helix ◽  
Human Parathyroid Hormone ◽  
Monte Carlo Simulated Annealing

β-sheet formation in BPTI(16–36) by Monte Carlo simulated annealing

1999 ◽  
Vol 299 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Yuko Okamoto ◽  
Masato Masuya ◽  
Miho Nabeshima ◽  
Takashi Nakazawa
Keyword(s):  
Monte Carlo ◽  
Simulated Annealing ◽  
Monte Carlo Simulated Annealing ◽  
Β Sheet
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