[AMBER] reference potential alchemical calculation

From: Pietro Vidossich via AMBER <amber.ambermd.org>
Date: Wed, 1 Nov 2023 01:34:42 +0000

Dear Amber developers and users, hope all is fine with you.


Iím writing to ask advice on the setup of a reference potential alchemical calculation transforming a pyridine from MM to QM potential in a box of MM water molecules. The way I understand it, is to have an empty qmmask (and ifqnt=1) for the MM calculation (in the manual I read that the qmmask selection can be empty). Doing so I receive the error:


QM ATOM VALIDATION: nquant has a value of 0

SANDER BOMB in subroutine validate_qm_atoms

nquant illegal

Need 0 < nquant <= natom


Instead if I set ifqnt=0 for the MM simulation, the calculation remains stuck at the very beginning (is active but does not produce any MD step).


I checked that the calculation runs and completes with icfe=1 and ifqnt=1 using the same or different (but not empty) qmmask selections in the two simulations.


I would kindly ask about the correct way to setup such calculation, which I read in the literature is available in sander.


Thank you in advance.


Best regards,


Pietro Vidossich

MMDD group

IIT, Genova, Italy
_______________________________________________
AMBER mailing list
AMBER.ambermd.org
http://lists.ambermd.org/mailman/listinfo/amber
Received on Tue Oct 31 2023 - 19:00:02 PDT
Custom Search