The Fourier Map generator and Viewer in WinGX is one of the main Killer Applications of this software suite in allowing powerful routine aid in structure solution and quality checking of the structure. (It should be noted that software such as Sir97, EXPO, GSAS and Platon also generate Fourier Contour Maps, but WinGX (and Platon?) is potentially the most accessible and convenient for non-Shelx generated structures to use) While optimised for working with Shelx, any application that can generate a Shelx *.ins structure file and a *.fcf (H K L Fobs, Fcalc) file can make use of this Fourier Viewing feature. Shelx generates an FCF file when using the LIST 3 command. WinGX generates the entire MAP file (which takes longer) but then allows people to quickly browse through the map, and also use its ANIMATE function to automatically scroll through the slices.

Due to the present lack of good publically distributable (published) examples (such as showing disorder or looking at finding templates in zeolites), the following example is taken from Marcus Bond's website of example datasets [Home | CCP14 Web Mirror]. In this case, the ladd5c structure.

Before starting out, you would normally do a cycle of refinement with Shelx93 or Shexl97 using the LIST 3 command to generate a Shelx FCF file which is then used by the Fourier Map Generator.

• Run WinGX to bring up the following Menu Bar

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• Confirming that you have generated an FCF file in Shelx using the LIST 3 command (or supplied an equivalent file), go into the MAPS, FOURIER MAP option via the top menu.

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• Select the 3D Fourier Option and the type of Map you want (in this case Fobs). Then select the range of the UNIT CELL you wish to view and the resolution (in this case, Z projection; -0.5 to +0.5 on all 3 axes; and at a resolution of 0.1 Angstrom).

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• To generate the Map file, press the OK button. This may take a while as WinGX is generating the entire map; but it will be fast on viewing later on.

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• To View the Map, select, MAPS, FOURIER MAP

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• Using the menus, you can label all the atoms (including symmetry equivalents) which will then display as you move near the slice they are physicaly located; change the density of the contours and the colour scheme. You can also Edit Copy to the clipboard or print out a hardcopy at any time.

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• You can go up in slices or play a movie of the Contour program automatically going up the slices.

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