[gmx-users] vdW cutoff

[Fabian Casteblanco]

Hello,

I am quite confused on whether it is better to use a standard cut-off
scheme for vdW interactions or if its better to use a switch or shift
function for this.  I am doing a free energy calculation on the
solvation of a drug molecule in a solvent (on CHARMM ff) so I want to
be as accurate as possible.  The CHARMM paper does state that they use
some type of switch function between 10 A and 12 A but I'm confused on
the difference between 'Switch' and 'Shift'.  I ran the solvents alone
using these different types and it seems to give similar results.  Is
this a major decision to getting accurate free energy calculations?
Will using standard 14 A cutoffs with DispersionCorrection=EnerPres be
enough?

Thanks for anyone with knowledge in this area.

-- 
Best regards,

Fabian F. Casteblanco
Rutgers University --
Chemical Engineering PhD Student
C: +908 917 0723
E:  fabian.casteblanco at gmail.com