[Pw_forum] (no subject)

Gabriele Sclauzero sclauzer at sissa.it
Thu Feb 4 11:28:17 CET 2010


My "semi-empirical" suggestion is to restart with ion_dynamics='damp' and see if the 
problem persist. Maybe you can do a few steps of damped dynamics and then restart again 
with BFGS. Probably this will not solve your problem, but you can give a try ;-)

HTH

GS


PS: you should chose better the subject of your posts next time...


Julen Ibanez Azpiroz wrote:
> Hello
> 
> I am trying to relax a system with unit cell made of 24 silicon atoms 
> and 2 talium atoms, one in each edge. I wish the system to be a surface, 
> so the unit cell has vacuum between the talium atoms so that they do not 
> "see" each other. I tried to relax it following the Example03 of Quantum 
> Espresso which is a surface of  "al001". In the example there are two 
> methods, I followed the first one, the one of the "bfgs" method. When I 
> use Scalar_Relativistic pseudopotentials (for both atoms) it is Ok, 
> after some trials the system relaxes. However, when I use Relativistic 
> pseudopotentials (for both atoms) the system cannot relax, after many 
> trials the system repeats the atomic configuration and stops. I have 
> tried both, to let all the atoms move and to let move just a few of the 
> surface, keeping the other fixed, but it does not work anyway. The most 
> I can get is that the force in every atom is smaller than 0.01Ry/au. 
> Both pseudopotentials work allright in simpler models. I would 
> appreciate any suggestion. Thank you very much
> 
> Julen
> 
> UPV/EHU, Fisica de la Matertia Condensada
> 
> 
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| Gabriele Sclauzero, PhD Student                  |
| c/o:   SISSA & CNR-INFM Democritos,              |
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