What is the difference between DFCOEF and DFPCMO?

Both files hold the MO coefficients (and some other information) and can be used to restart SCF calculations.

DFCOEF is always generated. To generate DFPCMO, you need the .PCMOUT keyword.

To see the difference between the two files, run a calculation with:

**GENERAL
.PCMOUT

and save both files from the scratch directory:

$ pam ... --get "DFCOEF DFPCMO"

and then inspect both files. You will see that only DFPCMO is human-readable. Both contain the same information. The DFCOEF file is machine-readable and machine-dependent which means that DIRAC cannot restart from a DFCOEF file generated on a different architecture but you can always restart from DFPCMO on any machine. The advantage of the DFCOEF file is that it is smaller in size (but with gzip you can compress DFPCMO files to the size of DFCOEF files). The advantage of DFPCMO files is that you can read them yourself (try to understand what the numbers mean) and use them in external scripts and programs.

You do not need any keywords for restarting, simply copy DFPCMO or DFCOEF to the scratch directory and DIRAC will restart automatically.

Try it. It is important that you know how to restart. This will save you many troubles and CPU hours.