Journal ArticleDOI
Indexing of powder diffraction patterns for low-symmetry lattices by the successive dichotomy method
A. Boultif,D. Louër +1 more
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TLDR
In this paper, a dichotomy method for indexing powder diffraction patterns for low-symmetry lattices is studied in terms of an optimization of bound relations used in the comparison of observed data with the calculated patterns generated at each level of the analysis.Abstract:
The dichotomy method for indexing powder diffraction patterns for low-symmetry lattices is studied in terms of an optimization of bound relations used in the comparison of observed data with the calculated patterns generated at each level of the analysis. A rigorous mathematical treatment is presented for monoclinic and triclinic cases. A new program, DICVOL91, has been written, working from the cubic end of the symmetry sequence to triclinic lattices. The search of unit cells is exhaustive within input parameter limits, although a few restrictions for the hkl indices of the first two diffraction lines have been introduced in the study of triclinic symmetry. The efficiency of the method has been checked by means of a large number of accurate powder data, with a very high success rate. Calculation times appeared to be quite reasonable for the majority of examples, down to monoclinic symmetry, but were less predictable for triclinic cases. Applications to all symmetries, including cases with a dominant zone, are discussed.read more
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A lithium superionic conductor
Noriaki Kamaya,Kenji Homma,Yuichiro Yamakawa,Masaaki Hirayama,Ryoji Kanno,Masao Yonemura,Takashi Kamiyama,Yuki Kato,Shigenori Hama,Koji Kawamoto,Akio Mitsui +10 more
TL;DR: A lithium superionic conductor, Li(10)GeP(2)S(12) that has a new three-dimensional framework structure that exhibits an extremely high lithium ionic conductivity of 12 mS cm(-1) at room temperature, which represents the highest conductivity achieved in a solid electrolyte, exceeding even those of liquid organic electrolytes.
Journal ArticleDOI
Powder pattern indexing with the dichotomy method
Ali Boultif,Daniel Louër +1 more
TL;DR: In this article, the DICVOL04 algorithm was extended to include a tolerance to the presence of impurity (or inaccurately measured) diffraction lines, a refinement of the zero-point position, a reviewing of all input lines from the solution found from, generally, the first 20 lines, and a cell analysis, based on the concept of the reduced cell, to identify equivalent monoclinic and triclinic solutions.
Journal ArticleDOI
FOX, `free objects for crystallography': a modular approach to ab initio structure determination from powder diffraction
TL;DR: In this article, a new program is developed for ab initio crystal structure determination from powder diffraction data (X-ray and neutron) using global optimization algorithms to solve the structure by performing trials in direct space.
Journal ArticleDOI
Cobalt carbide nanoprisms for direct production of lower olefins from syngas
Liangshu Zhong,Fei Yu,Fei Yu,Yunlei An,Yunlei An,Yonghui Zhao,Yuhan Sun,Yuhan Sun,Li Zhengjia,Li Zhengjia,Tiejun Lin,Yanjun Lin,Qi Xingzhen,Yuanyuan Dai,Lin Gu,Jin-Song Hu,Shifeng Jin,Qun Shen,Hui Wang +18 more
TL;DR: Detailed catalyst characterization during the initial reaction stage and theoretical calculations indicate that preferentially exposed {101} and {020} facets play a pivotal role during syngas conversion, in that they favour olefin production and inhibit methane formation, and thereby render cobalt carbide nanoprisms a promising new catalyst system for directly converting syng as into lower olefins.
Journal ArticleDOI
DASH: a program for crystal structure determination from powder diffraction data
William I. F. David,Kenneth Shankland,Jacco van de Streek,Elna Pidcock,W. D. Samuel Motherwell,Jason C. Cole +5 more
TL;DR: DASH as discussed by the authors is a user-friendly graphical-user-interface-driven computer program for solving crystal structures from X-ray powder diffraction data, optimized for molecular structures and includes algorithms for multiple peak fitting, unit-cell indexing and space-group determination.