>I can mention that I have already been able to optimize the geometry in Cartesian coordinates with constrained nuclei positions by using the keyword "IFREEZ" in "STATPT" section.
>I changed to delocalized coordinate because I want also to constrain some dihedral angles.
>As soon as I started to use "ZMAT" and DLCs, I got the problems that I mentioned in the first message: optimization does not converge and the energy not only decrease.
It is hard to help you not knowing details containing in the output file.
If you can share your output file with me, please do so.
You can attach it to this thread or send compressed file
to my private email address.
If you cannot share your output files, please post at least
the graphs on energy vs. geometry search step number
and max. energy gradient component vs. step number.
[ This message was edited on Tue Jun 17 '14 at 11:25pm by the author ]