formchk converts the data in a Gaussian checkpoint file into a formatted form which is suitable for input into a variety of visualization software.
formchk has the following syntax:
formchk [options] chkpt-file formatted-file
where chkpt-file is the name of the binary checkpoint file to be formatted, and formatted-file is the name for the resultant output file. For example, the following command will produce the formatted checkpoint file propell.fchk from the checkpoint file propell.chk:
$ formchk propell.chk propell.fchk
The conventional extension for formatted checkpoint files is .fchk on Unix systems and other computers supporting variable-length extensions, and .fck on systems which limit extension to three characters like Windows.
Note that formatted checkpoint files can be used as a data exchange format between computer platforms. Use formchk on the originating computer and unfchk on the target computer to create a binary checkpoint file. Always include the -3 option when moving files between different types of computers (see below).
By default formchk produces a formatted checkpoint file that is backwardly compatible with all previous versions of Gaussian.
-3
Produce a version 3 formatted checkpoint file, including all features supported in Gaussian 09.
-2
Produce a version 2 formatted checkpoint file. This was the version used with Gaussian 03.
-c
Causes the molecular mechanics atom types to appear in the formatted checkpoint file as strings rather than integers.
Last updated on: 10 May 2009