The input file for EXPO, created via the EXPO graphical user interface (GUI) or a text editor, contains commands (each command line begins with the % character) and directives (which must follow their corresponding command) to activate default and non-default strategies.
Each specific process is associated with a command and/or directives. The input file must contain at least two main commands:
-
%structurefollowed by a name (usually the name of the structure to be investigated) to identify the solution process. -
%datafollowed by directives that provide the minimum required information about the experimental powder diffraction data (data-file name, wavelength, and the type of radiation used to collect the data, if different from standard laboratory X-rays).
Other commands (and their directives) can be used depending on the tasks to be performed—primarily indexing, space group determination, structure solution by Direct Methods or structure solution by Direct Space methods —and other non default strategies.
It is here given an example of input file for EXPO, for carrying out the following sequential processes in a default way: indexing, space group determination and structure solution by Direct Methods. In this example, the command %job is used for printing a caption line in the output file, the command %ntreor is necessary to activate the indexation and the command %continue to execute all the rest of steps of the structure solution process.
%structure nbpo %job title nbpo powder data %data pattern nbpo.pow wavelength 1.0001 synchrotron %ntreor %continue