General NEB question with VaspSol

[jess_white]

Hi,

I was just wondering if I am able to run NEB calculations with VaspSol? Such as the following?
LSOL = .TRUE.
EB_K = 35

Also I was wondering if IOPT = 3 is the best way to go and how do you know when you should change the IOPT?

NSW = 500 (number of ionic steps)
ISMEAR = 0 (gaussian smearing method)
SIGMA = 0.05 (please check the width of the smearing)
IBRION = 3 (do MD with a zero time step)
POTIM = 0 (Zero time step so that VASP does not move the ions)
SPRING = -5.0 (spring force (eV/A2) between images)
LCLIMB = .TRUE. (turn on the climbing image algorithm)
ICHAIN = 0 (Indicates which method to run. NEB (ICHAIN=0) is the default)
IOPT = 3 (LBFGS = Limited-memory Broyden-Fletcher-Goldfarb-Shanno)
EDIFFG = -0.01


Many thanks in advance!

[graeme]

For sure, NEB with vaspsol is no problem

I like IOPT=3, but that is usually because I am debugging some problem calculation and that optimizer is very stable. IOPT=1 (and probably 7) should be faster, but it is also less stable and you need a sufficiently small INVCURV as appropriate for any high frequencies in the system. I suggest using IOPT=3 and when you see steady convergence, you can switch to IOPT=1 and see if you can speed things up with that. I also like to use IOPT=3 when there are high forces and when I see a sensible band and forces below 0.5 eV/Ang, switch to IOPT=1

[jess_white]

Thank you so much! I appreciate it :) Thank you also for the explanation as it made it super clear to me. Will be giving them a go now