Dear stefano, Thank you for your reply. Yes the energy is decreasing but I aborted the run after 14 scf cycles. I will repeat the run with the norm conserving potential and wait until it finish.
Best Regards, Hind Lecturer IT department King Abdulaziz University On Sun, Feb 18, 2018 at 10:12 AM, Stefano de Gironcoli <[email protected]> wrote: > is the energy decreasing ? if so the relaxation is not yet finished. > > stefano > > On 18/02/2018 02:55, Hind Almisbahi wrote: > > Dear experts of quantum espresso, > > I am doing relaxation and the problem is that the total force is > decreasing until the 4th scf, then start to increase gradually. The > system does not converge. Actually, I need to calculate the band structure > and see the band gap of Armchair graphene ribbon. The ribbon width is > composed of 17 carbon atoms (N=3p+2 family), so it is metallic. I have one > unit cell of the ribbon. I read in this mailing list many useful > discussions about suitable input for metallic systems and I followed them > as I understand. The version of quantum espresso is 6.1. > > I tried many options of the input script but all the runs have the same > problem, total force is decreasing until the 4th scf then start to > increase gradually. This is a complete version of my input: > > > > &CONTROL > > calculation='relax', > > outdir='.\Work', > > prefix='Arm17', > > pseudo_dir='C:\qe-6.1\pseudo', > > verbosity='high', > > etot_conv_thr= 1.0D-3, > > forc_conv_thr=1.0d-2, > > / > > &SYSTEM > > ibrav=8, > > a=41.1089d0, > > b=4.26258d0, > > c=20.0d0, > > nat=34, > > ntyp=1, > > ecutwfc=65, > > ecutrho=520, > > nbnd=76 > > occupations='smearing', > > smearing='marzari-vanderbilt', > > degauss=0.001d0, > > / > > > > &ELECTRONS > > conv_thr=1d-06, > > mixing_beta=0.7d0, > > mixing_mode='local-TF' > > mixing_ndim=12 > > diagonalization='cg' > > / > > > > &IONS > > / > > > > ATOMIC_SPECIES > > C 12.010700d0 C.pbe-rrkjus.UPF > > > > ATOMIC_POSITIONS {crystal} > > C 0.0336555229d0 0.6666666956d0 0.5000000000d0 > > C 0.0919486003d0 0.8333333913d0 0.5000000000d0 > > C 0.0336555229d0 0.3333333044d0 0.5000000000d0 > > C 0.1502416777d0 0.6666666956d0 0.5000000000d0 > > C 0.2085347551d0 0.8333333913d0 0.5000000000d0 > > C 0.0919486003d0 0.1666666087d0 0.5000000000d0 > > C 0.1502416777d0 0.3333333044d0 0.5000000000d0 > > C 0.2668277852d0 0.6666666956d0 0.5000000000d0 > > C 0.3251206731d0 0.8333333913d0 0.5000000000d0 > > C 0.2085347551d0 0.1666666087d0 0.5000000000d0 > > C 0.2668277852d0 0.3333333044d0 0.5000000000d0 > > C 0.3834141768d0 0.6666666956d0 0.5000000000d0 > > C 0.4417072068d0 0.8333333913d0 0.5000000000d0 > > C 0.3251206731d0 0.1666666087d0 0.5000000000d0 > > C 0.3834141768d0 0.3333333044d0 0.5000000000d0 > > C 0.5000002369d0 0.6666666956d0 0.5000000000d0 > > C 0.5582932669d0 0.8333333913d0 0.5000000000d0 > > C 0.4417072068d0 0.1666666087d0 0.5000000000d0 > > C 0.5000002369d0 0.3333333044d0 0.5000000000d0 > > C 0.6165862969d0 0.6666666956d0 0.5000000000d0 > > C 0.6748793269d0 0.8333333913d0 0.5000000000d0 > > C 0.5582932669d0 0.1666666087d0 0.5000000000d0 > > C 0.6165862969d0 0.3333333044d0 0.5000000000d0 > > C 0.7331723570d0 0.6666666956d0 0.5000000000d0 > > C 0.7914653870d0 0.8333333913d0 0.5000000000d0 > > C 0.6748793269d0 0.1666666087d0 0.5000000000d0 > > C 0.7331723570d0 0.3333333044d0 0.5000000000d0 > > C 0.8497584170d0 0.6666666956d0 0.5000000000d0 > > C 0.9080514470d0 0.8333333913d0 0.5000000000d0 > > C 0.7914653870d0 0.1666666087d0 0.5000000000d0 > > C 0.8497584170d0 0.3333333044d0 0.5000000000d0 > > C 0.9663444771d0 0.6666666956d0 0.5000000000d0 > > C 0.9080514470d0 0.1666666087d0 0.5000000000d0 > > C 0.9663444771d0 0.3333333044d0 0.5000000000d0 > > > > K_POINTS {automatic} > > 1 50 1 0 0 0 > > > > These are some of the many options that I have explored: > > The above potential is ultrasoft, I used also norm conserving > (C.pbe-mt_gipaw.UPF). > > Smearing: I used methfessel-paxton and marzari-vanderbilt > > Degause: I used 0.01 and 0.001 > > mixing_beta: I used 0.1 and 0.7 > > mixing_mode: I used local-TF and TF > > mixing_ndim: I used 8 and 12 > > diagonalization: I used cg and david > > ecutwfc: I used 65 and 75 > > ecutrho: with norm conserving (ecutwfc*4 and ecutwfc*10), with ultrasoft > (ecutwfc*8) > > nbnd=76 (I have 34 atoms, so 136 valence electrons which need 68 bands, > because it is metallic I added 8 extra bands) > > Previously I have successfully calculated the band structure and band gap > of semiconductor ribbon but I could not do the calculation of metallic > ribbon. I appreciate any help to solve my problem, why the forces always > increase after the 4th scf? > > > > Best Regards, > > Hind > > Lecturer, IT department > > King Abdulaziz University > > > _______________________________________________ > Pw_forum mailing > [email protected]http://pwscf.org/mailman/listinfo/pw_forum > > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- Disclaimer: The information contained in this message is intended for the addressee only and may contain classified information. If you are not the addressee, please delete this message and notify the sender; you should not copy or distribute this message or disclose its contents to anyone. Any views or opinions expressed in this message are those of the individual(s) and not necessarily of the university. No reliance may be placed on this message without written confirmation from an authorized representative of its contents. No guarantee is implied that this message or any attachment is virus free or has not been intercepted and amended. إخلاء مسؤليه: ان جميع المعلومات المتضمنة في هذه الرسالة تخص المستلم، وربما تتضمن معلومات سرية، واذا لم تكن انت المستلم فالرجاء الغاء الرسالة واشعار المرسل، كما يمنع نسخ او توزيع هذه الرسالة او افشاء محتوياتها لاخرين. ويجدر بالعلم ان جميع الآراء ووجهات النظر الواردة في هذه الرسالة تعتبر شخصية وليست بالضرورة منسوبة للجامعة. كما لايمكن ان يعتمد على هذه الرسالة ما لم تحصل على موافقة خطية من المسئول عن محتوياتها. كما لايوجد ضمان بان هذه الرسالة أو مرفقاتها خالية من الفيروسات أو انها لم يتم اعتراضها وتعديلها
_______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
