The Interactive Structure Factor Tutorial

Welcome to the structure factor tutorial! The aim of this tutorial is to learn about structure factors, phases, symmetry, and the relationship between the structure factors and the electron density map. The tutorial uses an interactive tool, the `structure factor applet'.

The applet window The structure factor applet has four windows. Top left is the control window, in which you can select reflections and set their values by entering values in the text boxes. Several buttons allow you to modify the structure factor values in the map and the diffraction pattern. Top right is the structure factor window, which shows the current diffraction pattern. Bottom left is the reflection window, with which you can view or modify magnitudes and phases. Bottom right is the map window, showing the unit cell and electron density.

Magnitudes and phases are encoded as colours using the same scheme as the Book of Fourier.

Small screen
or
slow browser

Miller Indices.
Structure factors(1).
Structure factors(2).
Symmetry(1).
Symmetry(2).
Pattersons(1).
Pattersons(2).
Direct Methods.

There are two versions of the structure factor tutorial. If you have a small screen (less than 1280x1024), or if you have a browser with a slow Java virtual machine (e.g. SGI machines), pick the links on the left.

If you have a big screen (at least 1280x1024), and a browser with a fast Java virtual machine (e.g. Sun, Linux, Windows), pick the links on the right.

If you are not sure about your machine, try both versions and use whichever works better for you.

Big screen
and
fast browser

Miller Indices.
Structure factors(1).
Structure factors(2).
Symmetry(1).
Symmetry(2).
Pattersons(1).
Pattersons(2).
Direct Methods.

Bugs and fixes

Most browsers with reliable Java implementations work fine, but if you have problems, please tell me. In general the only solution is for you to use a different web browser.

The Structure Factor Applet may be installed locally and/or customised for teaching topics not covered here, with certain conditions. If you wish to install the tutorial locally please email me for more details.

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Kevin Cowtan: