Powder Diffraction Crystallography of Molecular Solids

2011 ◽  
pp. 133-177 ◽  
Author(s):  
Kenneth D. M. Harris
Keyword(s):  
Powder Diffraction ◽  
Molecular Solids

scholarly journals PSSP, a computer program for the crystal structure solution of molecular materials from X-ray powder diffraction data

2010 ◽  
Vol 43 (2) ◽  
pp. 370-376 ◽  
Author(s):  
Silvina Pagola ◽  
Peter W. Stephens
Keyword(s):  
Crystal Structure ◽  
Computer Program ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Degrees Of Freedom ◽  
Space Structure ◽  
Molecular Solids ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Structure Solution

This work describes the computer programPSSP(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 thanRwp. The methodology outlined is applicable to organic solids composed of moderately complex rigid and flexible molecules, using diffraction data up to relatively low resolution.PSSPperformance tests using 11 molecular solids with six to 20 degrees of freedom are analyzed.

Principles of time resolved cars studies of molecular solids

1985 ◽  
Vol 82 ◽  
pp. 153-158 ◽  
Author(s):  
S.P. Velsko ◽  
R.M. Hochstrasser
Keyword(s):  
Molecular Solids ◽  
Time Resolved

Powder diffraction studies of organoammonium polymolibdates

2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 611-616
Author(s):  
B. Gaweł ◽  
W. Łasocha
Keyword(s):  
Powder Diffraction

New horizons for the structural characterization of stainless steel slags by X-ray powder diffraction

2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 61-66 ◽  
Author(s):  
B. Peplinski ◽  
B. Adamczyk ◽  
G. Kley ◽  
K. Adam ◽  
F. Emmerling ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Powder Diffraction ◽  
Structural Characterization ◽  
X Ray ◽  
New Horizons

X-ray Structure Refinement and Vibrational Spectroscopy of Ca8Gd2 (PO4)6 O2

2013 ◽  
Vol 12 (10) ◽  
pp. 719-726
Author(s):  
R. Ayadi ◽  
Mohamed Boujelbene ◽  
T. Mhiri
Keyword(s):  
Solid State ◽  
General Formula ◽  
Vibrational Spectroscopy ◽  
Powder Diffraction ◽  
Infrared Spectra ◽  
Solid State Reaction ◽  
Structure Refinement ◽  
Unit Cell ◽  
Cell Group ◽  
X Ray

The present paper is interested in the study of compounds from the apatite family with the general formula Ca10 (PO4)6A2. It particularly brings to light the exploitation of the distinctive stereochemistries of two Ca positions in apatite. In fact, Gd-Bearing oxyapatiteCa8 Gd2 (PO4)6O2 has been synthesized by solid state reaction and characterized by X-ray powder diffraction. The site occupancies of substituents is0.3333 in Gd and 0.3333 for Ca in the Ca(1) position and 0. 5 for Gd in the Ca (2) position.  Besides, the observed frequencies in the Raman and infrared spectra were explained and discussed on the basis of unit-cell group analyses.

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