[gmx-users] Scaling Coulomb interactions with lambda, on a pair-wise basis

[Matt Wyczalkowski]

Hi,

I am looking to scale non-bonded interactions between two atoms with the 
lambda parameter, while keeping other interactions unchanged.  I am not 
sure how to do this for Coulomb interactions.

Scaling the Lennard-Jones interactions between a specific atom pair 
seems straightforward, by setting VA, WA, VB, WB for that pair in the 
[PAIRS] directive.  However, in order to modify Coulomb interactions 
between an atom pair, it seems I need to modify qA and qB for each atom 
-- this then affects the interactions between this atom and all other 
atoms as well, something I need to avoid.

Is there a way to scale Coulomb interactions for a specific pair of 
atoms only?

Thanks in advance --

Matt

-- 
Matt Wyczalkowski
Doctoral Candidate, Biomedical Engineering
Pappu Lab: http://lima.wustl.edu
Washington University in St. Louis
maw2 at cec.wustl.edu