Crystal Structure Determination from Powder Diffraction Data by Monte Carlo Methods

Harris, Kenneth D. M.; Tremayne, Maryjane; Lightfoot, Philip; Bruce, Peter G.

doi:10.1021/ja00087a047

Cited by 317 publications

(256 citation statements)

References 2 publications

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“…The Monte Carlo method, used in the present study, follows the procedure described by Harris et al (1994), using the Metropolis importance sampling algorithm. The objective function was the weighted reliability index given by…”

Section: Finding Missing Atoms By the Monte Carlo Methodsmentioning

confidence: 99%

“…Direct methods require extraction of integrated intensities of individual re¯ections from the powder diffraction pattern and whether a structure can be solved or not depends on the percentage of independently resolved re¯ections (Estermann & Gramlich, 1993). On the other hand, the Monte Carlo method (Harris et al, 1994) and the simulated annealing method directly ®t the calculated pattern to the observed pattern and they do not require the integrated intensities. 1 Therefore, these methods are applicable not only to well resolved patterns, but also low-resolution data as often exhibited by organic materials.…”

Section: Introductionmentioning

confidence: 99%

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Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method

Tanahashi¹,

Nakamura²,

Yamazaki³

et al. 2001

Acta Crystallogr Sect B

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The crystal structure of 2,2-dihydroxymethylbutanoic acid (C 6 H 12 O 4 ) in monoclinic form has been determined ab initio from synchrotron radiation powder diffraction data. Two O and ®ve C atoms were ®rst derived by direct methods. Two missing O atoms and one C atom were found by the Monte Carlo method without applying constraint to their relative positions. Positional and isotropic displacement parameters of these non-H atoms were re®ned by the Rietveld method. Molecules are linked by hydrogen bonds and they make sheetlike networks running parallel to the (010) plane. The Monte Carlo method is demonstrated to be a powerful tool for ®nding missing atoms in partially solved structure.

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Section: Finding Missing Atoms By the Monte Carlo Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method

Tanahashi¹,

Nakamura²,

Yamazaki³

et al. 2001

Acta Crystallogr Sect B

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show abstract

“…Eugene Y. Cheung With the advances of direct space strategies for structure solution from powder data [1,2], and in particular the success of the Genetic Algorithm method [3,4], a fundamental question on what structural information can be extracted from the diffraction data of increasingly poor diffraction data must be addressed. Structural problems which have the complexity of more than one molecule in the asymmetric unit present new challenges to powder X-ray diffraction [5], and recent developments in the structure solution of complicated structures using powder diffraction techniques will be highlighted [6].…”

Section: S8m27p1mentioning

confidence: 99%

Structural aspects of the metal–insulator transition in BaVS₃

Fagot¹,

Foury²,

Pouget³

et al. 2004

Acta Cryst Sect A

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This study presents structural transitions of the one dimensional system BaVS 3 at low temperature by means of high resolution synchrotron powder diffraction. At room temperature the structure is hexagonal (P6 3 /mmc) with face sharing VS 6 octahedral chains along the c axis separated by Ba atoms leading to a V-V intrachain distance of 2.808(1)Å and an interchain distance 6.714(1)Å.The hexagonal structure at room temperature becomes orthorhombic (Cmc2 1 ) at 240K with a V straight chains transformed into uniform zigzag but without significant change in the electronic properties. At 70K a metal-insulator transition occurs with the appearance of a superstructure which doubles the chain periodicity. The structure refined at 40K revealed a weak monoclinic distorsion (b= 90.046(1)°) with 4 nonequivalent V sites. A valence bond analysis shows no evidence for charge disproportionation on these sites. However at 5K, the faces of the VS6 octahedra are stretched (site V1) or compressed (V3) inducing a 0.5e-charge disproportionation between the V1 and V3 sites. s8.m27.p1Towards an understanding of molecular crystals from powder X-ray diffraction techniques. With the advances of direct space strategies for structure solution from powder data [1,2], and in particular the success of the Genetic Algorithm method [3,4], a fundamental question on what structural information can be extracted from the diffraction data of increasingly poor diffraction data must be addressed. Structural problems which have the complexity of more than one molecule in the asymmetric unit present new challenges to powder X-ray diffraction [5], and recent developments in the structure solution of complicated structures using powder diffraction techniques will be highlighted [6].[1] Harris, K.D.M.; Tremayne, M.; Lightfoot, P.; Bruce, P.G.

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“…The new approach works in the direct space and exploits some additional information on the molecular geometry. Stereochemical parameters (bond distances, angles and torsion angles) are varied according to one of the following techniques: genetic algorithm (Harris et al, 1998), grid search (Chernyshev & Schenk, 1998), Monte Carlo (Harris et al, 1994), simulated annealing (Kirkpatrick et al, 1983). The selection of the most reliable model is carried out by comparing the observed and calculated pro®les.…”

Section: Introductionmentioning

confidence: 99%

Completion of crystal structure by powder diffraction data: a new method for locating atoms with polyhedral coordination

et al. 2002

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Ab initio crystal structure solution via powder diffraction data is often incomplete: frequently, the heavy atoms are correctly located but the lightatom positions are usually unreliable. The recently developed procedure POLPO [Altomare et al. (2000). J. Appl. Cryst. 33, 1305±1310], implemented in the EXPO program [Altomare et al. (1999). J. Appl. Cryst. 32, 339±340], aims at completing a partial structure model provided by direct methods by exploiting the prior information on the polyhedral coordination of the located atoms (tetrahedral or octahedral) and their connectivity. The POLPO procedure requires that all the cations are correctly labelled and rightly located. This condition does not always occur, particularly when the data quality is poor. A new method is described which is able to locate missing cations and surrounding anions when the cation coordination is tetrahedral or octahedral. The procedure has been successfully checked on different test structures.

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Crystal Structure Determination from Powder Diffraction Data by Monte Carlo Methods

Cited by 317 publications

References 2 publications

Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method

Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method

Structural aspects of the metal–insulator transition in BaVS₃

Completion of crystal structure by powder diffraction data: a new method for locating atoms with polyhedral coordination

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Crystal Structure Determination from Powder Diffraction Data by Monte Carlo Methods

Cited by 317 publications

References 2 publications

Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method

Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method

Structural aspects of the metal–insulator transition in BaVS3

Completion of crystal structure by powder diffraction data: a new method for locating atoms with polyhedral coordination

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Structural aspects of the metal–insulator transition in BaVS₃