Dear Dimpy, the default value for scf steps is 100. The message means that the code does not achieve the electronic convergence after 100 scf steps. This usually means that your initial electronic configuration is too far from the scf one and the algorithm does not manage to converge in 100 step. Or, that there exist "two" solutions and the algorithm is oscillating. If it is just a question of been to far there are two possibilities 1) the algorithm need just more scf steps, so you just need to increase electron_maxstep (default=100) or to decrease mixing_beta (or both) (attention the decrease of mixing beta might produce that the algorithm need also more electron step). 2) you are too far and "two" solutions are accessible. This is for instance what happens in SiO2 for the charged -1 and -2 oxygen interstitial, or the Si vacancy. For treating such a problem you need to first do a pre-relaxation with some trick. For the insterstitial it is better to start from a neutral relaxation, for the Si vacancy one need to relax first with a substituted Al. Sometimes it can also bee usefull to rpe-relax with electronic temperature to facilitate convergence (ad a broadening).
hope it can help you, bests Layla Quoting Dimpy Sharma <dimpy.sharma at tyndall.ie>: > > Hi Quantum espresso users, > > I have been trying to perform a relax calculation in my system with > 99 atoms (semiconductor system) and I am running my calculation in 48 > processors. The calculation has finished 3 scf steps and finished 100 > iterations, but after this it stops and it is showing me the > following message . > ' convergence NOT achieved after 100 iterations: stopping' > > I have restart my calculation, still I got the same error message > after 100 iteration steps. > > Can any body give me any suggestion? > > Thanks > > Dimpy > ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.
