Thank you, Tom. In that case, is the gamma point the best choice for me? On Tue, Dec 20, 2022 at 12:17 PM Tom Demeyere via users < [email protected]> wrote:
> In periodic codes, properties (total energy is one of them) are averaged > over the Brillouin zone. As a results you can’t do any assumption on how > this property will change when you change k-points, it may sometime > increase or sometime decrease, I don’t think this is unusual. > > On 20 Dec 2022, at 17:37, Rameswar Bhattacharjee <[email protected]> > wrote: > > > *CAUTION:* This e-mail originated outside the University of Southampton. > Hi Paolo, > Thank you very much for your reply and suggestion. It looks strange to me > as the energy eventually converges to a high value (~0.06 Ry higher) > compared to the first iteration energy. One more thing I found unusual is > that (as I mentioned earlier) the total energy obtained at the gamma point > is ~0.07 Ry higher than the total energy at any other k-points. I am not > much experienced with periodic calculation and never had such experience > with finite methods. > > Rameswar > > On Tue, Dec 20, 2022 at 11:28 AM Paolo Giannozzi <[email protected]> > wrote: > >> The energy is variational, that is: it goes down as self-consistency is >> approached. The energy term that makes the energy variational is however >> approximate and becomes exact only at self-consistency. As a consequence >> it may happen that at the beginning of the self-consistency the energy >> goes up instead of going down. Nothing to worry about as long as the >> energy eventually converges (monotonically from above) >> >> Paolo >> >> On 18/12/2022 19:23, Rameswar Bhattacharjee wrote: >> > >> > You don't often get email from [email protected]. Learn why this >> is >> > important <https://aka.ms/LearnAboutSenderIdentification> >> > >> > >> > Hi Everyone, >> > I am doing a single-point calculation on a 1D polymer in QE using >> > PBE-PAW. However, I am seeing an issue in the SCF iteration cycles. The >> > first iteration seems to print the right electronic energy but from >> > iteration 2 the energy suddenly increases significantly and then the >> SCF >> > ends up with higher energy. I am a little confused about how to >> > stabilize the SCF iteration so the energy does not go up. Any >> > suggestions will be highly appreciated. >> > >> > I am providing the output of the first three iterations of the SCF for >> > deep insights. >> > >> > >> ------------------------------------------------------------------------------ >> > >> > iteration #1 ecut= 120.00 Ry beta= 0.30 >> > >> > Davidson diagonalization with overlap >> > >> > ethr =1.00E-02,avg # of iterations =2.0 >> > >> > >> > negative rho (up, down):1.348E-04 0.000E+00 >> > >> > >> > total cpu time spent up to now is 13.7 secs >> > >> > >> > total energy=-304.41586797 Ry >> > >> > estimated scf accuracy< 2.72932626 Ry >> > >> > >> > iteration #2 ecut= 120.00 Ry beta= 0.30 >> > >> > Davidson diagonalization with overlap >> > >> > ethr =3.79E-03,avg # of iterations =1.0 >> > >> > >> > negative rho (up, down):1.006E-04 0.000E+00 >> > >> > >> > total cpu time spent up to now is 16.3 secs >> > >> > >> > total energy=-304.13553253 Ry >> > >> > estimated scf accuracy< 0.76532583 Ry >> > >> > >> > iteration #3 ecut= 120.00 Ry beta= 0.30 >> > >> > Davidson diagonalization with overlap >> > >> > ethr =1.06E-03,avg # of iterations =6.0 >> > >> > >> > negative rho (up, down):5.328E-05 0.000E+00 >> > >> > >> > total cpu time spent up to now is 19.4 secs >> > >> > >> > total energy=-304.26340272 Ry >> > >> > estimated scf accuracy< 0.08826578 Ry >> > >> > >> -------------------------------------------------------------------------------------------- >> > >> > Thanks >> > Rameswar Bhattacharjee >> > Georgetown University >> > >> > _______________________________________________ >> > The Quantum ESPRESSO community stands by the Ukrainian >> > people and expresses its concerns about the devastating >> > effects that the Russian military offensive has on their >> > country and on the free and peaceful scientific, cultural, >> > and economic cooperation amongst peoples >> > _______________________________________________ >> > Quantum ESPRESSO is supported by MaX (www.max-centre.eu >> <https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.max-centre.eu%2F&data=05%7C01%7CT.Demeyere%40soton.ac.uk%7C4832131b4f034299432508dae2a87da3%7C4a5378f929f44d3ebe89669d03ada9d8%7C0%7C0%7C638071510688622307%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=nMmVAsVbbq1HxQuArnILgNURUIuCC2ZMXfHWBlQOwTo%3D&reserved=0> >> ) >> > users mailing list [email protected] >> > https://lists.quantum-espresso.org/mailman/listinfo/users >> <https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.quantum-espresso.org%2Fmailman%2Flistinfo%2Fusers&data=05%7C01%7CT.Demeyere%40soton.ac.uk%7C4832131b4f034299432508dae2a87da3%7C4a5378f929f44d3ebe89669d03ada9d8%7C0%7C0%7C638071510688622307%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=tGIUyAzbz0ENtPd3j5hftmJtOxSWjv8DAJrVhnKTvTY%3D&reserved=0> >> >> -- >> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, >> Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216 >> > _______________________________________________ > The Quantum ESPRESSO community stands by the Ukrainian > people and expresses its concerns about the devastating > effects that the Russian military offensive has on their > country and on the free and peaceful scientific, cultural, > and economic cooperation amongst peoples > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users > > _______________________________________________ > The Quantum ESPRESSO community stands by the Ukrainian > people and expresses its concerns about the devastating > effects that the Russian military offensive has on their > country and on the free and peaceful scientific, cultural, > and economic cooperation amongst peoples > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________ The Quantum ESPRESSO community stands by the Ukrainian people and expresses its concerns about the devastating effects that the Russian military offensive has on their country and on the free and peaceful scientific, cultural, and economic cooperation amongst peoples _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
