[Pw_forum] Help with atomic relaxation (Issue with convergence)

[Vikas Varshney]

Dear Users,

I want to relax (not vc-relax) the combined system of Al2O3 slab with 2 or
3 layers of Ni-atoms on the top of it. Before this combined study, I have
successfully relax the Al2O3 slab and Ni layers seperately. When I combine
them together, I dont know (in advance) the seperation at which I should
keep the Ni layers on the top of Al2O3 slab. So, I keep it ~2 Angs apart
and was hoping that with relax, I should get a relaxed geometry.

The issue I am having is that the electronic relaxation is not converging
(1e-8) even after 500 steps (electron_maxstep = 500).
 I tried 1000 steps also. It ran through few iterations of atom relaxations
but then got crashed after few iterative steps (at a certain step).

So, I wanted to ask how I can make is equilibrate faster? Would a lower
value of conv_thr (1e-4 oe 1e-5)  at the initial stages help (to relax
atomic coordinates) for frequently. Once, I know the approximate good
positions for Ni, atoms, I could increase the conv_thr then.

Please guide, any other suggestions are also highly welcomed

Best Regards,
Vikas

Computational Reseacher,
Wright Patterson Air Force Base,
Dayton, OH.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20120123/8df80fe1/attachment.html>