When Levels 1 - 4 are selected, a Dialog Box will open. If possible, the information required for SIR92, i.e. unit cell data, space group symbol, number and type of atoms in cell etc, will obtained automatically, otherwise the user should enter or modify this information via the Dialog Box.
Alternatively, the user may wish to modify the input file SIR92.INS manually. This file is saved after SIR92 has executed, and so may be used for subsequent runs. In order to use a pre-existing input file, use the "Use SIR92file" Menu Item.