I did similar thing before, total energy doesn't need to converge... On Mon, Aug 23, 2010 at 2:22 AM, Guda Karthik <karthik.guda at gmail.com> wrote: > Hi, > > ??? The total energy doesn't converge till 80 Ryd of ecutwfc. I am using Ni > and Ti USPPs (Ti.pbe-sp-van_ak.UPF, Ni.pbe-nd-rrkjus.UPF). My calculations > become very slow while using such a large kinetic energy cutoff. am I doing > something wrong here? > > regards, > Karthik > > On Tue, Aug 17, 2010 at 4:46 PM, Stefano de Gironcoli <degironc at sissa.it> > wrote: >> >> please note that the two outputs that you submitted ARE NOT examples of >> vc-relaxation but of structural relaxation of the internal coordinates >> only. Your question is anyway legittimate... >> Are you sure to have converged the total energy of your system with >> respect to cutoff to a sufficient level ? >> when comparing ?different volumes one is using different basis sets in >> the two cases. If convergence w.r.t. cutoff is not sufficient this ?can >> lead to sudden decreases of the energy when increasing the volume. >> >> stefano >> SISSA and DEMOCRITOS >> >> Guda Karthik wrote: >> > Hi, >> > >> > ? ? Here are the input and output files. >> > >> > ? ? b19_Acklatpos_new.* - original structure >> > >> > ? ? b19_pwscf.* - scf calculation with a structure obtained after >> > vc-relax >> > >> > ? ? Please have a look if they are of help. >> > >> > regards, >> > Karthik >> > >> > On Sat, Aug 14, 2010 at 6:27 AM, Paolo Giannozzi >> > <giannozz at democritos.it>wrote: >> > >> > >> >> On Aug 4, 2010, at 4:41 , Guda Karthik wrote: >> >> >> >> >> >>> I am trying to relax an orthorhombic structure using vc-relax >> >>> (celldofree - xyz). I start with a structure which is at a Pressure >> >>> of -20.5 Kbar and at the end of the vc-relax I get a structure >> >>> which is at a pressure of -0.21 Kbar. Surprisingly, the structure >> >>> at pressure closer to zero is higher in energy than the original >> >>> structure by 8 * 10^-4 eV/formula unit. All the symmetry elements >> >>> have been conserved during relaxation and the initial and final >> >>> structures are the same. I am not able to make sense of this >> >>> result. I observe this inconsistency in my B2 structure as well. >> >>> Please help regarding this. >> >>> >> >> hard to help without input and output >> >> >> >> P. >> >> --- >> >> Paolo Giannozzi, Dept of Physics, University of Udine >> >> via delle Scienze 208, 33100 Udine, Italy >> >> Phone +39-0432-558216, fax +39-0432-558222 >> >> >> >> >> >> >> >> _______________________________________________ >> >> Pw_forum mailing list >> >> Pw_forum at pwscf.org >> >> http://www.democritos.it/mailman/listinfo/pw_forum >> >> >> >> >> > >> > >> > >> > >> > ------------------------------------------------------------------------ >> > >> > _______________________________________________ >> > Pw_forum mailing list >> > Pw_forum at pwscf.org >> > http://www.democritos.it/mailman/listinfo/pw_forum >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum > > > > -- > Karthik Guda > Graduate Student > Materials Engineering > Purdue University > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > >
-- Jia Chen Dept of Chemistry Princeton University Princeton, NJ 08544
