Restarts

For the most part, restarts with ADF QM/MM are the same as in a standard ADF run. In other words to specify a restart, one needs to use the RESTART keyword. This signals the QM/MM extension to read the data from the QM/MM restart file as opposed to the input. It is important to emphasize that the QM/MM extension has its own restart file. Thus, the user will have to keep track to two restart files, the standard ADF restart file (TAPE21) and the QM/MM restart file. By default the QM/MM restart file is 'mm.restart', but you can change this by using the RESTART_FILE keyword within the QMMM key block. A truncated example of an ADF QM/MM restart input is given below:.

RESTART ADF_restart.file & {same as in a standard ADF run}
 NOHESS
END

QMMM
 RESTART_FILE mm_restart.file {optional, with default filename of 'mm.restart'}
 FORCE_FIELD_FILE sybyl.ff 
 OUTPUT_LEVEL=1
 WARNING_LEVEL=1
 ...
 ...
 ...
END

At the moment, when the RESTART keyword is used, the QM/MM extension will always look for the QM/MM restart file. There is no way to bypass this. However, the QM/MM restart file is simply a text file whose contents resemble those of the QMMM key block in the ADF QM/MM input and you can easily modify it.

It is also important to note that the RESTART_FILE both specifies the file to be read at the beginning of a restarted run, and the file that will be written to. In an ADF QM/MM run that was restarted, the initial QM/MM restart file is overwritten.