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Re: [lammps-users] FEP calculation on charged cluster
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Re: [lammps-users] FEP calculation on charged cluster


From: Agilio Padua <agilio.padua@...24...>
Date: Wed, 22 Nov 2017 15:08:35 +0100

If the atoms in the cluster have charges of the same sign and they are increased in your perturbation (by +0.1) I would expect the chemical potential to go up due to repulsion.
Maybe I’m missing something.

Agilio

On 22 Nov 2017, at 02:21, Imanuel Kristanto <imanuelkristanto@...24...> wrote:

Thank you for your reply and thoughtful comments.
Some clarification on the system details.
The charge is not neutral during FEP calculation (the original charge is +1 after equilibrated by QEQ, the charge of each silver atom varies from 0.84-1.15). Additionally, for interaction between silver atoms are described by EAM potential.
So the unperturbed charge is based on QEQ equilibration is around 0.84 to 1.15.


On Wed, Nov 22, 2017 at 1:27 AM, Agilio Padua <agilio.padua@...24...> wrote:

I was trying to understand your problem but have some questions about your setup:

Is your system kept charge neutral during the FEP calculation? There can be large long range effects if not.

I don’t understand what is the unperturbed state: charges +1 or QEQ charges? If the latter, what are the typical values?

Agilio






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Best Regards,
Kristanto