From: WT Ren (
Date: Sun Jun 30 2019 - 09:42:13 CDT

Dear All:

I have been struggling to optimize the partial charges of one small
molecule obtained from CHARMM-GUI by fftk and gaussian for several days. I
followed the workflow in the tutorial, but unfortunately, the MM/QM
distances and energies did not converge. Some water molecules moved far
from the interaction site. I tried excluding those water molecules from the
optimization, then other water molecules would move away. It seems there
are some tricks in the charge optimization. Could anyone give me some
advice or tips on this issue. I will be very grateful for any guidance. I
can send the files if they would help.

PS: The ligand molecule includes two phosphates and carries -4 charges.