it is *.FA file contains forces (eV/Ang) Best wishe, Maxim.
2014-07-26 17:00 GMT+04:00 邵德喜 <dxshao...@gmail.com>: > Dear Maxim: > I'm so sorry to disturb you again,but I've completed the kpoint grid > convergence with a reletive high value of Meshcutoff just follow your > words.Then I've got many FORCE_STRESS files related to different kpoint > grid.In these files the first four lines is just as follows： > -1470.4169519132 > -0.000001407 -0.000000013 0.000000004 > -0.000000013 0.000000460 0.000000004 > 0.000000004 0.000000004 0.000050126 > I want to know what does the first line "-1470.4169519132" mean?And you've > told me the parameter used to convergence test is Force.Is Force you mean > the value " -1470.4169519132" or the next 3*3 matrix > -0.000001407 -0.000000013 0.000000004 > -0.000000013 0.000000460 0.000000004 > 0.000000004 0.000000004 0.000050126 > ? > Thans very very much . > Dexi Shao > > > 2014-07-25 20:39 GMT+08:00 邵德喜 <dxshao...@gmail.com>: > > Thanks very very much for all your replay,saluted all of you ! >> Dexi Shao >> >> >> 2014-07-25 19:22 GMT+08:00 Максим Арсентьев <ars21031...@gmail.com>: >> >> Yes, you right. >>> To clarify 1st keep fixed high meshcutoff and vary kpoint -> select >>> kpoint and keep it fixed but vary meshcutoff >>> Maybe this can be vice versa, or not,but possibly it is not so important >>> (final value of meshcutoff about 350-400 Ry, sometimes for late heavy >>> transition metal elements, with oxygen maybe it can be more) >>> >>> >>> 2014-07-25 5:53 GMT+04:00 邵德喜 <dxshao...@gmail.com>: >>> >>> I see.You mean that I should set CG steps as usual as we do structual >>>> relaxation(foer example :500) during all the convergence tests . >>>> And consider kpoint grid convergence first with a reletive high value >>>> of Meshcutoff.When it is done ,plot how it depends on FORCES from >>>> the output file in the final convergency step .Then consider meshcutoff >>>> convergence test with the convergency kpoint grid. >>>> When the convergence tests is completed ,structual relaxation is also >>>> completed,so I do not need to do structual relaxation additionally. >>>> Is it all right? >>>> Thanks for all your replay! >>>> ( PS: I‘m so sorry but the service is just out of work.I'll upload >>>> my input fdf file as soon as it recovers.) >>>> Dexi Shao >>>> >>>> >>>> 2014-07-25 1:14 GMT+08:00 Максим Арсентьев <ars21031...@gmail.com>: >>>> >>>> Dear Dexi! >>>>> >>>>> You should not set nember of CG steps to zero - it is not necessary. >>>>> You right that you should perform convergence of your property of >>>>> interest, >>>>> but first structural relaxation is important as I suppose - maybe not in >>>>> your case, but often it is so. So select high meshcutoff about 400-500 and >>>>> vary density of kpoint grid and plot how it depends on FORCES. From this >>>>> plot you will select kpoints, then take this kpoints fixed and vary >>>>> meshcutoff to plot dependence on forces again. It is forces, not total >>>>> energy are relevant for structural relaxation. Enter in google "graphene >>>>> transiesta" and 1st link will help I believe. >>>>> >>>>> четверг, 24 июля 2014 г. пользователь 邵德喜 написал: >>>>> >>>>> Thanks very much.The unit is Ry. >>>>>> I was told that when I get the original structure ,I should do >>>>>> convergence tests first,structual relaxation comes second. >>>>>> In my opinion ,do convergence test without structual relaxation I >>>>>> should set CG step to zero. >>>>>> problem1:I check the convergency (in terms of gradually increase >>>>>> Meshcutoff) of the total energy may be useless >>>>>> because I was told "we should check the convergence not of the total >>>>>> energy but of those properties which are relevant for our study in >>>>>> question >>>>>> ". >>>>>> But I just want to study the current-voltage relation ,it's expensive >>>>>> for me to check the convergence of its transport property. >>>>>> So I check the convergence of total energy instead opportunisticly. >>>>>> The input.fdf file is as follows. >>>>>> Thans for your replay. >>>>>> Dexi Shao >>>>>> >>>>>> >>>>>> 2014-07-24 18:22 GMT+08:00 Kanhao Xue <xuekan...@gmail.com>: >>>>>> >>>>>>> Dear Dexi, >>>>>>> >>>>>>> I wonder what is the unit of your Mesh cutoff? Is it in Ry? >>>>>>> >>>>>>> Siesta is using atomic orbital as the basis, which is quite >>>>>>> different from plane-wave based codes like VASP. In plane-wave code, the >>>>>>> plane wave cutoff energy directly determines your basis, and thus >>>>>>> influences the result a lot. >>>>>>> >>>>>>> In Siesta we have the mesh cutoff concept. A large cutoff is >>>>>>> required for accurate result. Usually for LDA, 250 Ry is sufficient and >>>>>>> for >>>>>>> GGA 350 Ry is sufficient. >>>>>>> >>>>>>> In my opinion you do not need to go up to 600 Ry to check. >>>>>>> >>>>>>> However, indeed your energy changes too much with Mesh cutoff. Can >>>>>>> you upload your input fdf file for more information? >>>>>>> >>>>>>> Kanhao >>>>>>> >>>>>>> >>>>>>> On Thu, Jul 24, 2014 at 11:43 AM, 邵德喜 <dxshao...@gmail.com> wrote: >>>>>>> >>>>>>>> Dear everyone: >>>>>>>> I have done the convergence test when I check the convergency (in >>>>>>>> terms of gradually increase Meshcutoff) of the total energy, I found >>>>>>>> that >>>>>>>> the Total energy rise up when I increase the parameter of Meshcutoff >>>>>>>> (please refer to the accesory) .Is it reasonable? >>>>>>>> Ahy replay will be appreciated. >>>>>>>> Dexi Shao >>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> >>>>>>> Sincerely yours, >>>>>>> Kanhao Xue >>>>>>> >>>>>>> Laboratoire de Réactivité et Chimie des Solides (LRCS) >>>>>>> UMR CNRS 7314 >>>>>>> Université de Picardie Jules Verne >>>>>>> 33 Rue Saint Leu, 80039 Amiens Cedex, France >>>>>>> >>>>>> >>>>>> >>>>> >>>>> -- >>>>> Best wishes, >>>>> Maxim Arsent'ev, D.Sc.(Chemistry) >>>>> Laboratory of research of nanostructures >>>>> Institute of Silicate Chemistry of RAS >>>>> >>>>> >>>> >>> >>> >>> -- >>> Best wishes, >>> Maxim Arsent'ev, D.Sc.(Chemistry) >>> Laboratory of research of nanostructures >>> Institute of Silicate Chemistry of RAS >>> >> >> > -- Best wishes, Maxim Arsent'ev, D.Sc.(Chemistry) Laboratory of research of nanostructures Institute of Silicate Chemistry of RAS
