On Thu, 2010-09-02 at 08:38 -0500, joaquin peralta wrote: > Thanks, i obtain more fast convergence for 1V/A, but ... > > If I use the previous results from 1V/A in order to calculate an > increase in the Field i obtain fluctuation in the energy. > > total energy = -261.46819272 Ry > total energy = -261.46815798 Ry > total energy = -261.46816720 Ry > total energy = -261.46260676 Ry > total energy = -261.37365516 Ry > total energy = -261.46820680 Ry > total energy = -261.46821935 Ry > total energy = -261.46807352 Ry > total energy = -261.46825528 Ry > total energy = -261.46820900 Ry > total energy = -261.46803348 Ry > > for my case, is recommendable reduce the precision by default of the > energy convergence from 1D-4 to 1D-3?
To what energy threshold are you referring: conv_thr (in &electrons) or etot_conv_thr (in &control). According to the value of 1d-3/1d-4 I would assume the latter; note however that the latter has nothing to do with the SCF convergence, as it is an optimization threshold criteria for geometry optimizer. If you use 1d-4 for the conv_thr, then the value is much too high, it should be 1d-6 or, even better, lower than that. After how many SCF cycles these "fluctuations" appear? You may try to reduce mixing_beta to 5%, ... The following considerations will speed-up your calculations, hence you will be able to do more SCF convergence tests: from the previous emails of yours, I notice that you use over 50 Angs of vacuum, which is HUGE (I would assume that about 25 Angs should be sufficient; in this case there will be more than 10 Angs spacing from the slab to the dipole-layer). I also noticed that ecutwfc/ecutrho of 30/500 ry is a very large number for Aluminum. Regards, Tone -- Anton Kokalj J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia (tel: +386-1-477-3523 // fax:+386-1-477-3822) Please, if possible, avoid sending me Word or PowerPoint attachments. See: http://www.gnu.org/philosophy/no-word-attachments.html
