Hi Charmm

Why is the QChem module being enabled by default in c41a1?
It breaks certain QM/MM options with the DFTB module.

E.g. Do a simple compilation to enable the DFTB module like:

./install.com gnu T gfortran +DFTBMKL

and you cannot use the REMOVE option (Classical energies within QM atoms are removed) in the SCCDFTB group. The offending check is in nbonds/nbonds.src line 316, and should never affect the DFTB module from CHARMM.

It is of course pretty easy to fix by editing install.com and removing qchem from the default option (this in turn messes up the if clauses in mndo97_ltm.src, however, but also trivial to fix).
So there any reason the QChem module is enabled by default as I think it is not at all necessary for most users anyway?

Anders Christensen

Last edited by andersx; 11/05/15 11:41 PM.