Dear Prof. Laurence Marks Sir, Thank you for your email. Sir, we have obtained the following results by using the above procedure;
Expt. Theory a=12.134 a=11.8071 b= 3.87 b=3.8838 c= 11.23 c=10.9285 Whether these are acceptable results? with regards, On Wed, 12 Aug 2020 at 18:53, Laurence Marks <laurence.ma...@gmail.com> wrote: > I have an impression that you have asked before about optimization, in > fact many times! > > A question you should ask yourself is what are you trying to achieve? DFT > is not a perfect theory, and while you can improve the agreement with > experiment using better (and slower) methods, in general experiment is more > accurate. > > If your calculations are close to experiment, e.g. atoms at positions > maybe 0.01 Angers off, that is all you can expect. > > If, for instance, the positions are 0.1 Angers off, and/or it is a metal > whereas in experiment it is an insulator, then something is very wrong. No > amount of lattice optimization is going to help. > > So, my question to you is are you killing defenseless electrons in a quest > to overfit data, or is there a reason? > > _____ > Professor Laurence Marks > "Research is to see what everybody else has seen, and to think what nobody > else has thought", Albert Szent-Gyorgi > www.numis.northwestern.edu > > On Wed, Aug 12, 2020, 08:11 shamik chakrabarti <shamik15041...@gmail.com> > wrote: > >> Also after obtaining the c/a optimized struct file with optimized lattice >> parameter & nearly optimized atomic coordinates for a hexagonal system I do >> a force minimization by keeping the lattice parameter intact (as obtained >> from c/a optimization curve). Whether this will give a wrong minima? >> >> with regards, >> >> On Wed, 12 Aug 2020 at 18:17, shamik chakrabarti < >> shamik15041...@gmail.com> wrote: >> >>> Dear Prof. Blaha, >>> >>> I have done some calculations by keeping both lines >>> active. What it does; >>> (!) It runs first runsp_lapw -ec 0.0001 for a given struct file >>> (2) After getting the energy convergence, it does the force minimization >>> for the given structure & saves the successive struct files as case_i.scf >>> for i=1,2.... >>> (3) after getting the force optimized structure it saves the optimized >>> struct files in case....._default.struct. >>> >>> What I do I take the optimized struct file which is near the minima i.e, >>> say case_coa____-5.00 _default .struct for next calculation & put the >>> lattice parameters in this file by calculating it by hand from c/a >>> optimized curve. >>> >>> Is this give the wrong minimum? >>> >>> Looking forward to your response in this regard. >>> >>> with regards, >>> >>> On Wed, 12 Aug 2020 at 17:59, Peter Blaha <pbl...@theochem.tuwien.ac.at> >>> wrote: >>> >>>> You certainly don't want both lines active. >>>> >>>> For a simultaneous optimization of internal coordinates, the >>>> recommended >>>> command in optimize.job is to add -min to the run-command: >>>> >>>> runsp_lapw -nlvdw -fc 1 -ec 0.001 -min >>>> >>>> An older alternative (usually not recommended) is: >>>> >>>> min -I -j "runsp_lapw -nlvdw -I -fc 1.0 -i 40 " >>>> >>>> >>>> On 8/12/20 11:03 AM, shamik chakrabarti wrote: >>>> > Dear Wien2k users, >>>> > I have edited the optimized.job by >>>> > uncommenting the following two lines for running simultaneous >>>> > optimization of atomic coordinates with a,b,c: >>>> > >>>> > runsp_lapw -nlvdw -ec 0.0001 >>>> > >>>> > min -I -j "runsp_lapw -nlvdw -I -fc 1.0 -i 40 " >>>> > >>>> > Is this method is correct? >>>> > >>>> > Looking forward to hearing from you. >>>> > >>>> > Thanks in advance >>>> > >>>> > with regards, >>>> > >>>> > -- >>>> > Dr. Shamik Chakrabarti >>>> > Research Fellow >>>> > Department of Physics >>>> > Indian Institute of Technology Patna >>>> > Bihta-801103 >>>> > Patna >>>> > Bihar, India >>>> > >>>> > _______________________________________________ >>>> > Wien mailing list >>>> > Wien@zeus.theochem.tuwien.ac.at >>>> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >>>> <https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!DI73f-Re7inuxswiG0HG_WW_8qHNkinbKZvm5h73PnAPN071cMfFjL8iMl1H3LfS79oWIw$> >>>> > SEARCH the MAILING-LIST at: >>>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >>>> <https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!DI73f-Re7inuxswiG0HG_WW_8qHNkinbKZvm5h73PnAPN071cMfFjL8iMl1H3LdFLbcbAw$> >>>> > >>>> >>>> -- >>>> >>>> P.Blaha >>>> >>>> -------------------------------------------------------------------------- >>>> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna >>>> Phone: +43-1-58801-165300 FAX: +43-1-58801-165982 >>>> Email: bl...@theochem.tuwien.ac.at WIEN2k: http://www.wien2k.at >>>> <https://urldefense.com/v3/__http://www.wien2k.at__;!!Dq0X2DkFhyF93HkjWTBQKhk!DI73f-Re7inuxswiG0HG_WW_8qHNkinbKZvm5h73PnAPN071cMfFjL8iMl1H3LckRMua-Q$> >>>> WWW: http://www.imc.tuwien.ac.at/TC_Blaha >>>> <https://urldefense.com/v3/__http://www.imc.tuwien.ac.at/TC_Blaha__;!!Dq0X2DkFhyF93HkjWTBQKhk!DI73f-Re7inuxswiG0HG_WW_8qHNkinbKZvm5h73PnAPN071cMfFjL8iMl1H3Ld00IoRBg$> >>>> >>>> -------------------------------------------------------------------------- >>>> _______________________________________________ >>>> Wien mailing list >>>> Wien@zeus.theochem.tuwien.ac.at >>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >>>> <https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!DI73f-Re7inuxswiG0HG_WW_8qHNkinbKZvm5h73PnAPN071cMfFjL8iMl1H3LfS79oWIw$> >>>> SEARCH the MAILING-LIST at: >>>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >>>> <https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!DI73f-Re7inuxswiG0HG_WW_8qHNkinbKZvm5h73PnAPN071cMfFjL8iMl1H3LdFLbcbAw$> >>>> >>> >>> >>> -- >>> Dr. Shamik Chakrabarti >>> Research Fellow >>> Department of Physics >>> Indian Institute of Technology Patna >>> Bihta-801103 >>> Patna >>> Bihar, India >>> >> >> >> -- >> Dr. Shamik Chakrabarti >> Research Fellow >> Department of Physics >> Indian Institute of Technology Patna >> Bihta-801103 >> Patna >> Bihar, India >> _______________________________________________ >> Wien mailing list >> Wien@zeus.theochem.tuwien.ac.at >> >> https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!DI73f-Re7inuxswiG0HG_WW_8qHNkinbKZvm5h73PnAPN071cMfFjL8iMl1H3LfS79oWIw$ >> SEARCH the MAILING-LIST at: >> https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!DI73f-Re7inuxswiG0HG_WW_8qHNkinbKZvm5h73PnAPN071cMfFjL8iMl1H3LdFLbcbAw$ >> > _______________________________________________ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > -- Dr. Shamik Chakrabarti Research Fellow Department of Physics Indian Institute of Technology Patna Bihta-801103 Patna Bihar, India
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