DIRDIF - FOUR

FOUR Fourier program

FOUR is a program for the calculation of a Fourier or Patterson map. It implies calculation of distances and angles, assignment and shuffling of new peaks into connected atoms, plotting of the asymmetric part of the structure, and finally arranging for recycling of a part of the structure. Note that the program's decision of which peaks to assign and which atoms to use is only preliminary, and the user apply his chemical knowledge to his local graphical system to make the final decisions.

The program uses input files generated by other programs. It is automatically called after the execution of other programs.

When the user calls for FOUR, the system will automatically arrange for structure factor calculation and then call FOUR for a default Fourier synthesis. Alternatively, the user can select other options at an interactive terminal session.