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Purpose
Crystal structure solution from powder or single crystal diffraction data using a combined global
optimization of the difference between calculated and measured diffraction
pattern and of the potential energy of the system ("Pareto optimization").
Functions
Structure Solution:
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Structure solution from conventional X-ray laboratory diffractometer as well as
synchrotron, neutron or electron diffraction data
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Input required:
- unit cell parameters
- diffraction data: either powder diffraction data (integrated intensities at Bragg angles
(not profile/step-scan data), imported from Philips, Bruker-AXS, Stoe), or single crystal diffraction data
(I(hkl), |F(hkl)| or F2(hkl)), e.g. imported from SHELX-file
- contents of the unit cell (composition or molecular structure plus
number of the formula units)
- "Wizard" for the easy preparation of the input data
- Automatic adjustment of all structure solution calculation parameters
- Calculation of profile patterns from experimental and calculated peak lists,
instead of just comparing the intensities of correlated peaks.
By doing so, the R-factor calculation is much less sensitive to 2theta errors
and wrong peak assignments. In earlier versions of Endeavour, this problem
frequently lead to wrong R-factor values and could prevent a whole crystal
structure from being solved.
- Automatic space group determination from resulting structure
- Optional or automatic check/correction of 2theta errors.
- Automatic checking of peak correlations (optional, active by default).
- Several "advanced settings", e.g. flexible molecules, jump widths, peak triangles, Simulated Annealing
parameters etc. - available from the structure solution wizard.
- Crystal structures containing molecules/rigid bodies can now be solved directly in a space group other than P1, even if their atoms must be placed on special positions.
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Viewing of the intermediate steps of the structure solution process: progress
(% finished), R-Value and overall cost function, list of correlated calculated and observed peaks,
structure picture, and diffraction diagram in user-defined arrangement
side-by-side.
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Auto Build function to visualize the crystal structure of each intermediate
step, e.g. the unit cell, with or without bonds, with or without polyhedras,
molecules, etc.
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Report View displaying the results of Pareto optimization as formatted text,
that can be copied to clipboard, saved, or printed.
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Easy editing, calculation, and fitting of potential parameters (simple
repulsion, Lennard-Jones).
- Minimum interatomic distances for all element pair combinations (derived from
Pearson's Crystal Data) are now implemented (no need for manual adjustment of parameters
for the simple repulsion potential anymore)
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Support for molecular as well as for atomic crystal structures. Molecules
can be fixed at certain positions and may rotate along a reference
atom.
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Symmetry Finder with automatic or interactive transformation to higher space
group.
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"Structure Solution" by either energy minimization or diffraction data alone is
possible. Manual selection of rotatable bonds within the molecule(s) for
variation during structure solution calculation.
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Import of 3-dimensional molecular structures from various file formats including
Diamond (*.dsf), Cambridge CSD-FDAT (*.dat, *.fdat, *.csd), MDL Molfile/SDFile
(e.g. from ACD ChemSketch) (*.mol, *.mdl, *.sd), Cerius2 CSSR (*.cssr, *.dat),
Sybyl MOL/MOL2 (*.mol, *.mol2) and CIF (*.cif) files.
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Molecules can also be sketched and transformed into 3D using ACD ChemSketch
Freeware which can be installed from the Endeavour 1.x CD-ROM.
Structure Visualization:
- Settings for the structure visualization "Autobuild" function (e.g. molecules,
polyhedra) are now adjusted automatically, taking into account the "chemistry"
of the compound under investigation
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Manual input or change of structural parameters and bibliographic data.
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Imports structure data from crystal structure databases (Inorganic Crystal
Structure Database, Cambridge Structural Database, Protein Data Bank), from
Pauling File (Inorganic Material Database), from Crystallographic Information
File (CIF), from SHELX format, as well as from several molecular structure
formats.
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Creating contents of unit cell, super-cell, or any arbitrary range of the
crystal lattice.
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Discussion of connectivity assisted by histograms showing the distribution of
distances between selected atom types, together with automatic calculation of
distance ranges.
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Completion of coordination spheres around selected atoms.
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Generation of molecules or completion of molecular fragments that have been
clipped at the cell edges (packing diagrams).
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Ball-and-stick, wire, and space filling model. Central or parallel projection,
depth cueing, stereo display.
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Photo-realistic rendered models with user-defined light source and material
properties (OpenGL).
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Rotating, shifting, and zooming: mouse-controlled, step-by-step by keyboard, or
numerically. Views along specified axes or towards hkl-planes.
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Coordination polyhedra around selected atoms or manually constructed, with
hatched, opaque, or transparent faces.
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Display of thermal ellipsoids to visualize anisotropic displacement parameters.
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Labelling of atoms and bonds. Variation of colors, styles and radii of atoms
and bonds, either by type or individually assigned.
General:
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32 Bit MS Windows application with tabbed Multiple Document
Interface (MDI), context-sensitive menus, and toolbars. Allows "simultaneous"
handling of multiple structures.
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User-defined arrangement of structure picture and diffraction diagram as well
as several textual data side-by-side.
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Multiple-step Undo and Redo function.
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Calculation or interactive measuring of distances, angles, and torsion angles,
including standard uncertainties.
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Export to crystal and molecular structure formats, peak and |F(hkl)| formats,
Windows metafile, several bitmap formats, as well as to Virtual Reality
Modelling Language (VRML).
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Online update (automatic or manual).
System requirements
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Personal computer with MS Windows® XP, Vista, Windows 7, Windows 8/8.1 or Windows 10 operating system (does not run on Windows RT or Windows 10 S or Windows 10 in "S mode")
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Microsoft Internet Explorer 5.01 or higher
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64 MB of RAM
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100 MB of free disk space
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Graphics resolution of 1024 x 768 pixels with 32,768 colors ("High Color")
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