New techniques for indexing: N-TREOR in EXPO

Indexing of a powder diffraction pattern is still a critical point in procedures aiming at solving crystal structures from powder data. New code has been associated to the program TREOR90 in order to define an efficient peak search procedure, to modify the crystallographic decisions coded into TREOR90 to make it more exhaustive, to refine the selected unit cell automatically, and to make the entire procedure user friendly, via a graphical interface. The new program, called N-TREOR, has been integrated into the package EXPO to create a suite of programs able to provide a structural model from the analysis of the experimental pattern. N-TREOR is also available as a stand-alone program.

[1]  F. Wu,et al.  Correction of zero shift in powder diffraction patterns using the reflection-pair method , 1999 .

[2]  Cheng Dong,et al.  POwderX: Windows-95-based program for powder X-ray diffraction data processing , 1999 .

[3]  Maria Cristina Burla,et al.  EXPO: a program for full powder pattern decomposition and crystal structure solution , 1999 .

[4]  C. Baerlocher,et al.  Synthesis and Structural Characterization of MWW Type Zeolite ITQ-1, the Pure Silica Analog of MCM-22 and SSZ-25 , 1998 .

[5]  K. Shankland,et al.  Crystal Structure Determination from Powder Diffraction Data by the Application of a Genetic Algorithm , 1998 .

[6]  K. Harris,et al.  The application of a genetic algorithm for solving crystal structures from powder diffraction data , 1997 .

[7]  H. Schenk,et al.  Crystal Structure of Anilinium Pentamolybdate from Powder Diffraction Data. The Solution of the Crystal Structure by Direct Methods Package POWSIM , 1997 .

[8]  P. Bruce,et al.  Ab initio solution of a complex crystal structure from powder-diffraction data using simulated-annealing method and a high degree of molecular flexibility , 1997 .

[9]  A. Le Bail,et al.  Structure of zeolitic K2 Ti Si3 O9 . (H2 O) determined ab initio from powder diffraction data , 1997 .

[10]  A. Meden,et al.  Rietveld refinement of the as synthesized and partially calcined forms of the molecular sieve GaPO4-ZON , 1997 .

[11]  K. Knight,et al.  Crystal structure of BaMo3O10 solved from powder diffraction data , 1997 .

[12]  Massimo Moret,et al.  The Multiphase Nature of the Cu(pz) and Ag(pz) (Hpz = Pyrazole) Systems: Selective Syntheses and Ab-Initio X-ray Powder Diffraction Structural Characterization of Copper(I) and Silver(I) Pyrazolates , 1994 .

[13]  Kenneth D. M. Harris,et al.  CRYSTAL STRUCTURE DETERMINATION FROM POWDER DIFFRACTION DATA BY MONTE CARLO METHODS , 1994 .

[14]  B. Roos,et al.  Crystal Structure of 2-[N-Morpholino]ethane Sulfonic Acid Hydrate, C6H15NO5S , 1993 .

[15]  M. Tournoux,et al.  Nb3(NbO)2(PO4)7 a Novel Niobium(V) Oxophosphate: Synthesis and Crystal Structure Determination from High Resolution X-Ray Powder Diffraction. , 1993 .

[16]  A. Fitch,et al.  Structure of the Lowest Temperature Phase of the Solid Benzene–Hexafluorobenzene Adduct† , 1992 .

[17]  L. McCusker,et al.  Ab initio structure determination from severely overlapping powder diffraction data , 1992 .

[18]  T. Wroblewski,et al.  Structure of Y4O(OH)9NO3 from x-ray and neutron powder diffraction data , 1992 .

[19]  P. Krogsgaard‐Larsen,et al.  Hydrogen bonds in the structure of BaC2C4.D2O , 1992 .

[20]  D. Louër,et al.  Indexing of powder diffraction patterns for low-symmetry lattices by the successive dichotomy method , 1991 .

[21]  Helmer Fjellvåg,et al.  The crystal structure of Cr8O21 determined from powder diffraction data: Thermal transformation and magnetic properties of a chromium-chromate-tetrachromate , 1991 .

[22]  Anthony K. Cheetham,et al.  The structure of cimetidine (C10H16N6S) solved from synchrotron-radiation x-ray powder diffraction data , 1991 .

[23]  A. Fitch,et al.  The structure of KUO2PO4.3D2O refined from neutron and synchrotron-radiation powder diffraction data , 1991 .

[24]  A. Fitch,et al.  The crystal structures of Ag4Ge7O16·6D2O and Na3(ND4)Ge7O16·6D2O refined from high resolution synchrotron radiation and neutron powder diffraction data , 1991 .

[25]  Erich Kleinpeter,et al.  The crystal structure of PbS2O3 , 1991 .

[26]  A. Fitch,et al.  The structure of solid dichlorodifluoromethane CF2Cl2 by powder neutron diffraction , 1991 .

[27]  Trevor J. Sears,et al.  Renner-Teller, spin-orbit and Fermi-resonance interactions in X 2Π NCS investigated by LIF spectroscopy , 1990 .

[28]  Siegfried Corbelin,et al.  Über Metallalkyl‐ und ‐aryl‐Verbindungen, 44 Darstellung und Struktur von Methylnatrium. Strukturbestimmung an NaCD3‐Pulvern bei 1.5 und 300 K durch Neutronen‐ und Synchrotronstrahlenbeugung , 1990 .

[29]  L. McCusker.  The ab initio structure determination of Sigma-2 (a new clathrasil phase) from synchrotron powder diffraction data , 1988 .

[30]  T. C. Huang.  Precision peak determination in X-ray powder diffraction , 1988 .

[31]  A. Cheetham,et al.  The synthesis and structure determination from powder diffraction data of LaMo5O8, a new oxomolybdate containing Mo10 clusters , 1988 .

[32]  Direct methods and structures showing superstructure effects.II. A probabilistic theory of triplet invariants , 1987 .

[33]  C. Giacovazzo,et al.  Direct methods and superstructures. I. Effects of the pseudotranslations on the reciprocal space , 1985 .

[34]  Lars Eriksson,et al.  TREOR, a semi-exhaustive trial-and-error powder indexing program for all symmetries , 1985 .

[35]  T. C. Huang,et al.  Accurate and rapid reduction of experimental x‐ray data , 1975 .

[36]  Werner P-E.  A fortran program for least-squares refinement of crystal-structure cell dimensions. , 1970 .

[37]  A. Savitzky,et al.  Smoothing and Differentiation of Data by Simplified Least Squares Procedures. , 1964 .