No. I didn't relax the molecule. As a matter of fact, I got this structure from want code's self test, and thought it was already relaxed-.- I'll relax it later and see if good things happen.
Best, -- Jin Zhang Dep. of Physics, Peking Univ. On 11/20/06, degironc <degironc at sissa.it> wrote: > > did you relaxed the structure ? > These are the forces I get with your input [a typical threshold for a > structural relaxation is > forc_conv_thr REAL ( default = 1.0D-3 ) ]. > stefano > > Forces acting on atoms (Ry/au): > > atom 1 type 2 force = -0.06870568 0.00011605 0.00070580 > atom 2 type 1 force = 0.00057171 -0.00133033 0.00026104 > atom 3 type 2 force = -0.03470840 0.06008037 > 0.00060235 > atom 4 type 1 force = -0.00200170 -0.00052894 -0.00023669 > atom 5 type 2 force = 0.03477692 0.05989867 -0.00004091 > atom 6 type 1 force = 0.00029793 0.00027534 - > 0.00032982 > atom 7 type 2 force = 0.06862846 -0.00002844 -0.00054894 > atom 8 type 1 force = -0.00256825 0.00128897 -0.00025706 > atom 9 type 2 force = 0.03495275 -0.06050673 - > 0.00040942 > atom 10 type 1 force = -0.00020204 0.00131722 0.00025463 > atom 11 type 2 force = -0.03450037 -0.05925204 0.00020053 > atom 12 type 1 force = 0.00345864 -0.00133014 -0.00020152 > > Total force = 0.169286 Total SCF correction = 0.000107 > > stefano > > > Jin Zhang wrote: > > > Dear MMC, > > > > The supercell I used is a simple cubic one (let ibrav=8 > > celldim(1,2,3)=20bohr). Because the molecule is isolated, I think the > > kpoint sampling should be irrelevant. And I used gamma point for the > > calculation. > > > > I increased ecut to 25Ry, and celldim to 30bohr) the number of > > negative modes increase by 9 (to 21modes)! > > OMG, there must be sth wrong! > > I'll attach my input and see if someone can give some comments. > > !-----------------------omega------------------- > > omega( 1) = -123.660534 [THz] = -4124.898815 [cm-1] > > omega( 2) = -122.070631 [THz] = -4071.865015 [cm-1] > > omega( 3) = -109.408034 [THz] = -3649.483445 [cm-1] > > omega( 4) = - 103.611190 [THz] = -3456.120267 [cm-1] > > omega( 5) = -100.288151 [THz] = -3345.274863 [cm-1] > > omega( 6) = -86.921490 [THz] = -2899.408087 [cm-1] > > omega( 7) = -86.648147 [THz] = - 2890.290289 [cm-1] > > omega( 8) = -78.536226 [THz] = -2619.703943 [cm-1] > > omega( 9) = -63.552993 [THz] = -2119.913758 [cm-1] > > omega(10) = -60.437624 [THz] = -2015.995524 [cm-1] > > omega(11) = - 59.290658 [THz] = -1977.736621 [cm-1] > > omega(12) = -59.022664 [THz] = -1968.797246 [cm-1] > > omega(13) = -58.953578 [THz] = -1966.492750 [cm-1] > > omega(14) = -46.326804 [THz] = -1545.306104 [cm-1] > > omega(15) = -31.263942 [THz] = -1042.859776 [cm-1] > > omega(16) = -31.093207 [THz] = -1037.164629 [cm-1] > > omega(17) = - 27.758798 [THz] = -925.939988 [cm-1] > > omega(18) = - 27.694407 [THz] = -923.792135 [cm-1] > > omega(19) = -24.097859 [THz] = -803.823410 [cm-1] > > omega(20) = -20.675736 [THz] = - 689.672916 [cm-1] > > omega(21) = -20.064562 [THz] = -669.286187 [cm-1] > > omega(22) = 15.218497 [THz] = 507.637805 [cm-1] > > omega(23) = 16.277849 [THz] = 542.974191 [cm-1] > > omega(24) = 20.249558 [THz] = 675.457041 [cm-1] > > omega(25) = 21.320279 [THz] = 711.172668 [cm-1] > > omega(26) = 22.104349 [THz] = 737.326626 [cm-1] > > omega(27) = 23.427206 [THz] = 781.452687 [cm-1] > > omega(28) = 30.392570 [THz] = 1013.793763 [cm-1] > > omega(29) = 43.644315 [THz] = 1455.827328 [cm-1] > > omega(30) = 55.006552 [THz] = 1834.833267 [cm-1] > > omega(31) = 57.997854 [THz] = 1934.613035 [cm-1] > > omega(32) = 61.898591 [THz] = 2064.728462 [cm-1] > > omega(33) = 68.862483 [THz] = 2297.020463 [cm-1] > > omega(34) = 68.979827 [THz] = 2300.934652 [cm-1] > > omega(35) = 69.303015 [THz] = 2311.715098 [cm-1] > > omega(36) = 69.697807 [THz] = 2324.884051 [cm-1] > > > > On 11/19/06, *Miguel Mart?nez Canales* < wmbmacam at lg.ehu.es > > <mailto:wmbmacam at lg.ehu.es>> wrote: > > > > Hi Jin, > > > > Jin Zhang escribi?: > > > The thing I cannot understand is, there're 12 negative frequencies > > > existing. I know 3 of them are purely translational modes and > > another 3 > > > are rotational ones. But what about the rest 6? I'm a little > > confused > > > and hopefully someone can help. > > > > > > The eigenvals are pasted below and thanks in advance! > > > > > > (the result may not be accurate due to a only-15Ry ecut I used, > > but it > > > should not give out qualitative different result) > > > > For a start, I wouldn't think 15 rydbergs is enough. Have you > > tested the > > pseudopotentials for ecut convergence? 25 or 30 would probably be > > a better > > choice. Anyway, what you probably are missing most in your > > calculations is > > k-point sampling convergence. Translational and rotational > > frequencies are > > a bit too large. What happens if you increase your k-point grid? > > Anyway, > > don?t forget to relax your molecule with the new parametres. > > > > BTW: What kind of cell are you using? I've never done molecular > > normal mode > > calculations but I guess that in the case of bencene using an > > hexagonal > > supercell might make sense. > > > > -- > > ---------------------------------------- > > Miguel Mart?nez Canales > > Dto. F?sica de la Materia Condensada > > UPV/EHU > > Facultad de Ciencia y Tecnolog?a > > Apdo. 644 > > 48080 Bilbao (Spain) > > Fax: +34 94 601 3500 > > Tlf: +34 94 601 5437 > > ---------------------------------------- > > > > "The problem with Renault is that they dont have > > the skills to convince FIA that the mass damper > > is just a brake cooler." > > > > Annonymous > > > > _______________________________________________ > > Pw_forum mailing list > > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org> > > http://www.democritos.it/mailman/listinfo/pw_forum > > > > > > > > > > -- > > Jin Zhang > > Dep. of Physics, > > Peking Univ. > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -------------- next part -------------- An HTML attachment was scrubbed... URL: /pipermail/attachments/20061120/cf5f17ef/attachment.htm
