Determination of alloy interatomic potentials from liquid-state diffraction data

2002 ◽  
Vol 66 (1) ◽  
Author(s):  
M. I. Mendelev ◽  
D. J. Srolovitz
Keyword(s):  
Diffraction Data ◽  
Liquid State ◽  
Interatomic Potentials

FIDDLE. Simultaneous Indexing and Structure Solution from Powder Diffraction Data using a Genetic Algorithm and Correlation Functions

2019 ◽  
Author(s):  
Carmen Guguta ◽  
Jan M.M. Smits ◽  
Rene de Gelder
Keyword(s):  
Genetic Algorithm ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Correlation Functions ◽  
Cross Correlation ◽  
Simultaneous Optimization ◽  
Powder Diffraction Data ◽  
Structure Solution ◽  
Matching Technique

A method for the determination of crystal structures from powder diffraction data is presented that circumvents the difficulties associated with separate indexing. For the simultaneous optimization of the parameters that describe a crystal structure a genetic algorithm is used together with a pattern matching technique based on auto and cross correlation functions.<br>

Structural Determination of the Hydrofullerene C60D36 by Neutron Diffraction

1998 ◽  
Vol 54 (3) ◽  
pp. 345-350 ◽  
Author(s):  
L. E. Hall ◽  
D. R. McKenzie ◽  
R. L. Davis ◽  
M. I. Attalla ◽  
A. M. Vassallo
Keyword(s):  
Neutron Diffraction ◽  
Density Function ◽  
Diffraction Data ◽  
Fourier Transformation ◽  
Structural Determination ◽  
Molecular Models ◽  
Reduced Density ◽  
C Nmr

A mixture of C60D36 with 24.5 \pm 4.5% C60 by weight has been analysed by neutron diffraction techniques. The diffraction data was converted to a reduced density function G(r) by Fourier transformation. The C60 component of the G(r) was subtracted out. This enabled a comparison for five molecular models of C60D36, with symmetries T, Th , S 6 and two D 3 d isomers, with the experimental G(r). This specimen of C60D36 was found to be best described by a T symmetry isomer, in agreement with 13C NMR and IR data for C60H36 [Attalla et al. (1993). J. Phys. Chem. pp. 6329–6331].

Combined Experimentaland Theoretical Determination of the Atomic Structure of the (310) Twin in NB

1991 ◽  
Vol 238 ◽  
Author(s):  
Geoffrey H. Campbells ◽  
Wayne E. King ◽  
Stephen M. Foiles ◽  
Peter Gumbsch ◽  
Manfred Rühle
Keyword(s):  
High Resolution ◽  
Theoretical Models ◽  
High Resolution Electron Microscopy ◽  
Interatomic Potentials ◽  
Image Simulation ◽  
Theoretical Determination ◽  
Atomic Structures ◽  
Resolution Electron ◽  
High Resolution Images

ABSTRACTA (310) twin boundary in Nb has been fabricated by diffusion bonding oriented single crystals and characterized using high resolution electron microscopy. Atomic structures for the boundary have been predicted using different interatomic potentials. Comparison of the theoretical models to the high resolution images has been performed through image simulation. On the basis of this comparison, one of the low energy structures predicted by theory can be ruled out.

scholarly journals Crystallization and X-ray diffraction data analysis of human deoxyhaemoglobin A0 fully stripped of any anions

1999 ◽  
Vol 55 (11) ◽  
pp. 1914-1916 ◽  
Author(s):  
F. A. V. Seixas ◽  
W. F. de Azevedo ◽  
M. F. Colombo
Keyword(s):  
Diffraction Data ◽  
Oxygen Affinity ◽  
X Ray Diffraction ◽  
Structural Explanation ◽  
Human Haemoglobin ◽  
X Ray ◽  
High Resolution Structure ◽  
Allosteric Properties

In this work, initial crystallographic studies of human haemoglobin (Hb) crystallized in isoionic and oxygen-free PEG solution are presented. Under these conditions, functional measurements of the O2-linked binding of water molecules and release of protons have evidenced that Hb assumes an unforeseen new allosteric conformation. The determination of the high-resolution structure of the crystal of human deoxy-Hb fully stripped of anions may provide a structural explanation for the role of anions in the allosteric properties of Hb and, particularly, for the influence of chloride on the Bohr effect, the mechanism by which Hb oxygen affinity is regulated by pH. X-ray diffraction data were collected to 1.87 Å resolution using a synchrotron-radiation source. Crystals belong to the space group P21212 and preliminary analysis revealed the presence of one tetramer in the asymmetric unit. The structure is currently being refined using maximum-likelihood protocols.

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