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Frequently Asked Questions

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Eva Myers edited this page Jan 10, 2022 · 3 revisions

How do I install DASH?

DASH runs under Windows 10 and 11. To install it go to https://github.com/ccdc-opensource/dash/releases and download and run the latest release installer.

How should I reference DASH?

DASH: a program for Crystal Structure Determination from Powder Diffraction Data.
W. I. F. David, K Shankland, J. van de Streek, E. Pidcock, W. D. S. Motherwell, J. C. Cole. J. Appl. Cryst., 39, 910-915, 2006
[DOI: 10.1107/S0021889806042117]

Structure Solution and Refinement of Tetracaine Hydrochloride from X-ray Powder Diffraction Data.
H. Nowell, J. P. Atfield, J. C. Cole, P. J. Cox, K. Shankland, S. J. Maginn, W. D. S. Motherwell, New J. Chem., 26, 469-472, 2002
[DOI: 10.1039/b109494g]

Structure Characterization of Three Crystalline Modificatins of Telmisartan by Single Crystal and High-resolution X-ray Powder Diffraction.
R. E. Dinnebier, P. Sieger, H. Nar, K. Shankland, W. I. F. David, J. Pharm. Sci., 89, 1465-1479, 2000
[DOI: 10.1002/1520-6017(200011)89:11<1465::AID-JPS9>3.0.CO;2-C]

Routine Determination of Molecular Crystal Structures from Powder Diffraction Data.
W. I. F. David, K. Shankland, N. Shankland, Chem. Commun., 931-932, 1998
[DOI: 10.1039/a800855h]

Indexing of Powder Diffraction Patterns for Low-symmetry Lattices by the Successive Dichotomy Method.
A. Boultif, D. Louër, J. Appl. Cryst., 24, 987-993, 1991
[DOI: 10.1107/S0021889891006441]

Is it possible to refine (preferably with constraints) the bond distances and angles of the molecule I am using?

Yes, it is possible to refine bond distances and angles during simulated annealing by manually editing the Z-matrix file (see the Z-matrix format Appendix for more details). Please note: DASH will also allow this during the additional Rietveld step.​

Why am I having problems with the RIETAN-FP output format from DASH?

The format of the files used as input to RIETAN has changed quite significantly between RIETAN-2000 and RIETAN-FP. DASH currently recognises whether RIETAN-2000 or FP is being used based on the name of the RIETAN executable set in the configuration dialogue. In the RIETAN-Venus package, however, the executable for FP is no longer called rietan-fp.exe, but simply rietan.exe. In the future there will be a check-box available in the configuration dialogue to define whether RIETAN 2000 or FP is being used, but as a work-around it is possible to simply rename the executable to rietan-fp.exe and then DASH should output the correct format of files.

N.B. The interfaces to third-party refinement packages in DASH are kept as up-to-date as possible, but no support is provided by the CCDC for these external programs.​

Are there any limits on the size of structure that DASH can solve?

There are no hard-coded limits on the size of molecule that DASH can handle. However, for large structures with many torsion angles (>15) structure solution will be difficult and good data are a necessity. There is a maximum of 1000 peaks that are allowed in the diffraction pattern.

DASH can handle multicomponent systems: salt, solvates, and other structures with more than one molecule in the asymmetric unit.​

How many z-matrices can I input to the "Molecular Z-Matrices" window of DASH?

The number of Z-matrices which can be read in to DASH has been increased from 4 to 32, with up to 8 copies per Z-matrix. For counter-ions etc., multiple copies of the same Z-matrix should be used.

Which file formats are supported?

​ DASH supports the following Powder Diffraction File formats:

  • .raw - Bruker
  • .raw - STOE
  • .rd and .sd - Philips
  • .udf, .uxd and .xye
  • .cpi - Sietronics
  • .mdi - Materials Data Inc.
  • .pod - Daresbury
  • .x01 - Bede​
  • .txt - ThermoARL
  • .asc - Rigaku
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