**2QMDFF [prefix1] [prefix2] **

If qmdffgen is called with a keyfile, the prefix of the QM reference for two QMDFFs is given.

Depending on the used software package, the following files must be present:

• Orca: prefix.log and prefix.hess
• Gaussian: prefix.out and prefix.chk, as well as the formchk utility program from Gaussian in the PATH variable
• CP2K: prefix.out