From either an Icon in MS-Windows (or typing expo on UNIX command line), run expo.

• This brings up the following screen

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• Click on OK and you are then prompted to open up a sir97 control file.

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• The file we are going to look at here is the default test file, cime. Following is the information inside the file that you would be expect to edit manually and is described in the EXPO manual [Home Site] | [CCP14 Mirror].

  %struct cime
  %job cimetidine -- Synchrotron data
  %init
  %data
  range  8.01 84.99 0.01
  pattern cime.pow
  cont s 4 c 40 n 24 h 64
  wave 1.52904
  cell     10.6986  18.8181 6.8246       90.000   111.284    90.000
  space p 21/n
  sync
  double
  %extraction
  %continue
  

• Click on the Browse to view what input files are available and click on the cime.exp file.

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• Click on OK to confirm your selection.

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• Then click OK again to let EXPO go through its stuff (like Sir97 this is the fun to watch bit). At various points, the program stops to give you the choice of changing the defaults. In this example, all you have to do is keep pressing the CONTINUE button.

  At this point, you can redefine the range of the data on which the structure factor extraction is performed

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• Click continue and EXPO will select what it considers to be the best intervals for the analysis. You can over-ride this if you which. For this example, we don't wish to over-ride anything, so just press CONTINUE

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• EXPO determines the background. You can zoom and inspect this, but we will just accept this and CONTINUE.

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• EXPO tries to determine the best peak profile to use, the goes about extracting intensities in the "regions" it selected - in this case "Region 2".

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• Now it is continuing onto "Region 3".

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• Now EXPO does an extraction cycle on the full pattern.

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• EXPO is now finished the extracting of intensities and now we can proceed for the direct methods by pressing CONTINUE.

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• EXPO now is Phasing.

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• EXPO is now attempting to place Atoms.

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• EXPO now is assigning elements to the atoms (in this case, Pink is Nitrogen, Red is Sulphur, Light Blue is Carbon).

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• EXPO now presents a structure to us.

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• As per Sir97, we can rotate the sample around. Those who refer to schematic structure of cimitidine in Adrich (1996 to 1996) page 394 (28,541-2) will see the connectivity and atom assignments seem to closely match eachother.

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• The above statement is more obvious if we change the PLOT STYLE to include atom labels.

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Rietveld in EXPO

• It is possible to do Rietveld in EXPO and set parameters to be released as a function of cycle number.

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• as per Sir97, Fourier difference or Obs maps are possible for finding residual atoms.

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• It is possible (again as per Sir97) to look through the contour maps at the electron density.

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