Yes! there is a tiny barrier of 0.005 Ry Arash
On 2017-04-19 00:20, Stefano de Gironcoli wrote: > Is there an energy barrier between the minimum found by relax and the > one you find varying the angle ? > > stefano > (sent from my phone) > >> On 18 Apr 2017, at 21:54, sarashs <[email protected]> wrote: >> >> They use exactly the same cuttoffs, K-points and everything >> (unfortunately.) but the near equilibrium energies are slightly less >> than equilibrium one. For instance for SiOZr angle at equilibrium I >> get: >> >> ! total energy = -245.22924923 Ry >> Harris-Foulkes estimate = -245.22924923 Ry >> estimated scf accuracy < 3.9E-12 Ry >> >> The total energy is the sum of the following terms: >> >> one-electron contribution = -715.79581276 Ry >> hartree contribution = 369.08543112 Ry >> xc contribution = -57.16353294 Ry >> ewald contribution = 158.66552815 Ry >> Dispersion Correction = -0.02086281 Ry >> >> And for SiOZr angle at equiliberium-25 I get: >> >> ! total energy = -245.23454839 Ry >> Harris-Foulkes estimate = -245.23454839 Ry >> estimated scf accuracy < 1.7E-12 Ry >> >> The total energy is the sum of the following terms: >> >> one-electron contribution = -739.45020087 Ry >> hartree contribution = 380.81843421 Ry >> xc contribution = -57.19470926 Ry >> ewald contribution = 170.61520075 Ry >> Dispersion Correction = -0.02327322 Ry >> >> Which is similar in terms of total energy but slightly lower and >> that's >> weird. Is there anything I can do to force QE to use the same basis >> set >> throughout SCF calculations? >> >> >>>> On Tuesday, 18 April 2017 17:10:25 CEST sarashs wrote: >>>> the other SCF's not have higher energy than the >>>> equilibrium angle regardless of them being optimized with a >>>> constraint? >>>> I mean if the structure is originally relax (which it is) then one >>>> expects other near equilibrium structures to have higher energies. >>>> Am >>>> I >>>> wrong there? >>> >>> You are right. >>> >>> They should be higher, which usually means less negative. As long as >>> the same >>> pseudopotentials, cutoffs, k-points and everything else is used. >>> >>> Do they? >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
