Dear Linh, Thank you for your response. So, do you suggest that I should increase the supercell size (by the same amount of d increase) each time I increase the value of d?
Thanks, On Tue, Jan 26, 2010 at 11:02 AM, Ngoc Linh Nguyen <nnlinh at sissa.it> wrote: > > When I plot the graph, it looks like ecutwfc =60 is optimal. Is it > right? Is it the right way to do > it? Is the final energy (obtained > from last relaxation step) the right quantity? > I think what you did for checking E vs. ecutwfc is right. However, with > the big model it could be quite expensive. You can do like that: you > choose an ecutwfc value firstly, for example ecutwfc = 40 Ry, and relax > your model with that value, then increase the value ecutwcf and run scf > only, you can obtain a relation E vs. ecutwfc in similar. > > > For Final energy (obtained from last relaxation step) vs d interlayer > distance at cutoff ecutwfc = 50.0: > > .... ecutwfc = 60.0 > I am confusing about increasing of d values in your models. > If you keep the sizes of supercell unchanged, when increasing the > value of d, the 3rd layer of the above supercell and 1st layer of the > below supercell should be approached too close together, i.e. , let try > visualizing by Xcryden at different values of d. And it can reduce an > increase of energy of your models as d is lager. > > Good luck, > Linh > mohamed sabri majdoub wrote: > > Dear all, > > > > I run calculations of 1 layer of graphene on bilyaer boron nitride. > > I am trying to study the Energy vs cutoff and Energy vs interlayer > > distance d between the graphene layer and top of BN layer. > > I got the following results after several runs. Is it the right way to > > do it? > > Here is the input file I am using: > > > ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- > > &control > > title = 'GphBN' > > calculation = 'relax' > > outdir = '/pwscf/pwscftemp' > > prefix = 'GphBN' > > pseudo_dir = '/pseudopot-C-B-N' > > tprnfor = .t. > > restart_mode = 'from_scratch' > > wf_collect = .true. > > disk_io = 'low' > > / > > &system > > ibrav = 0, > > celldm(1) = 1.8897261 > > nat = 72, > > ntyp = 3, > > ecutwfc = 60.0 > > occupations = 'smearing' > > smearing = 'gaussian' > > degauss = 0.003675 > > > > / > > &electrons > > mixing_mode = 'local-TF' > > mixing_beta = 0.05 > > diagonalization = 'david' > > conv_thr = 1.D-5 > > / > > &ions > > trust_radius_ini = 0.10 > > > > / > > &cell > > > > ATOMIC_SPECIES > > B 10.81100 B.pz-vbc.UPF > > C 12.01070 C.pz-vbc.UPF > > N 14.00674 N.pz-vbc.UPF > > ATOMIC_POSITIONS angstrom > > B 0.710000 8.607000 11.306000 > > B 0.710000 11.066000 11.306000 > > B 2.840000 7.377000 11.306000 > > B 0.710000 6.148000 11.306000 > > B 6.390000 6.148000 8.000000 > > B 6.390000 8.607000 8.000000 > > B 6.390000 11.066000 8.000000 > > B 2.840000 9.836000 11.306000 > > B 7.100000 7.377000 11.306000 > > B 7.100000 9.836000 11.306000 > > B 7.100000 12.295000 11.306000 > > B 4.970000 11.066000 11.306000 > > B 2.840000 12.295000 11.306000 > > B 4.970000 6.148000 11.306000 > > B 4.970000 8.607000 11.306000 > > B 4.260000 7.377000 8.000000 > > B 2.130000 11.066000 8.000000 > > B 2.130000 8.607000 8.000000 > > B 2.130000 6.148000 8.000000 > > B 4.260000 9.836000 8.000000 > > B 0.000000 7.377000 8.000000 > > B 0.000000 9.836000 8.000000 > > B 4.260000 12.295000 8.000000 > > B 0.000000 12.295000 8.000000 > > C 2.130000 6.148000 14.106000 > > C 2.130000 8.607000 14.106000 > > C 2.130000 11.066000 14.106000 > > C 0.000000 12.295000 14.106000 > > C 0.000000 9.836000 14.106000 > > C 0.000000 7.377000 14.106000 > > C 0.710000 11.066000 14.106000 > > C 0.710000 8.607000 14.106000 > > C 0.710000 6.148000 14.106000 > > C 6.390000 8.607000 14.106000 > > C 6.390000 6.148000 14.106000 > > C 4.970000 11.066000 14.106000 > > C 6.390000 11.066000 14.106000 > > C 7.100000 12.295000 14.106000 > > C 7.100000 9.836000 14.106000 > > C 7.100000 7.377000 14.106000 > > C 4.970000 8.607000 14.106000 > > C 2.840000 12.295000 14.106000 > > C 2.840000 9.836000 14.106000 > > C 2.840000 7.377000 14.106000 > > C 4.260000 7.377000 14.106000 > > C 4.970000 6.148000 14.106000 > > C 4.260000 12.295000 14.106000 > > C 4.260000 9.836000 14.106000 > > N 0.000000 12.295000 11.306000 > > N 0.000000 9.836000 11.306000 > > N 0.000000 7.377000 11.306000 > > N 2.840000 7.377000 8.000000 > > N 2.840000 9.836000 8.000000 > > N 2.840000 12.295000 8.000000 > > N 4.970000 11.066000 8.000000 > > N 4.970000 8.607000 8.000000 > > N 4.970000 6.148000 8.000000 > > N 7.100000 12.295000 8.000000 > > N 7.100000 9.836000 8.000000 > > N 7.100000 7.377000 8.000000 > > N 0.710000 6.148000 8.000000 > > N 0.710000 8.607000 8.000000 > > N 0.710000 11.066000 8.000000 > > N 6.390000 11.066000 11.306000 > > N 6.390000 8.607000 11.306000 > > N 6.390000 6.148000 11.306000 > > N 2.130000 11.066000 11.306000 > > N 2.130000 8.607000 11.306000 > > N 2.130000 6.148000 11.306000 > > N 4.260000 12.295000 11.306000 > > N 4.260000 9.836000 11.306000 > > N 4.260000 7.377000 11.306000 > > K_POINTS automatic > > 10 10 1 1 1 0 > > CELL_PARAMETERS > > 8.51980 0.00000 0.00000 > > 0.00000 7.37600 0.00000 > > 0.00000 0.00000 22.6120 > > > ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- > > The results are : > > > > 1- Final energy (obtained from last relaxation step) vs cutoff (ecutwfc) > > > > cut20: Final energy = -857.6291985882 Ry > > cut30: Final energy = -876.5012327526 Ry > > cut40: Final energy = -885.4765196610 Ry > > cut50: Final energy = -890.0493283821 Ry > > cut60: Final energy = -892.0114549785 Ry > > cut70: Final energy = -892.8706506804 Ry > > cut80: Final energy = -893.2520149989 Ry > > > > When I plot the graph, it looks like ecutwfc =60 is optimal. Is it > > right? Is it the right way to do it? Is the final energy (obtained > > from last relaxation step) the right quantity? > > > > > ------------------------------------------------------------------------------------------------------------------------------------------------------------ > > 2- For Final energy (obtained from last relaxation step) vs d > > interlayer distance at cutoff ecutwfc = 60.0: > > > > d=2.5= Final energy = -892.0122348924 Ry > > d=3.0= Final energy = -892.0119194861 Ry > > d=3.1= Final energy = -892.0089055437 Ry > > d=3.2= Final energy = -892.0104083862 Ry > > d=3.3= Final energy = -892.0115677649 Ry > > d=3.4= Final energy = -892.0113018510 Ry > > d=3.5= Final energy = -892.0121118001 Ry > > d=3.6= Final energy = -892.0113544429 Ry > > d=3.7= Final energy = -892.0096184164 Ry > > d=3.9= Final energy = -892.0041914533 Ry > > > > There are fluctuations in the data? Is it normal? > > > ----------------------------------------------------------------------------------------------------------------------------------------------------- > > > > 3- For Final energy (obtained from last relaxation step) vs d > > interlayer distance at cutoff ecutwfc = 50.0: > > > > d=2.5= Final energy = -890.0504214490 Ry > > d=2.8= Final energy = -890.0503533642 Ry > > d=2.9= Final energy = -890.0503471460 Ry > > d=3.0= Final energy = -890.0486572147 Ry > > d=3.1= Final energy = -890.0491375298 Ry > > d=3.2= Final energy = -890.0480863744 Ry > > d=3.3= Final energy = -890.0492074574 Ry > > d=3.4= Final energy = -890.0501303488 Ry > > d=3.6= Final energy = -890.0488317041 Ry > > d=3.5= Final energy = -890.0492797825 Ry > > d=3.7= Final energy = -890.0470527582 Ry > > d=3.8= Final energy = -890.0443250729 Ry > > d=3.9= Final energy = -890.0412177248 Ry > > > > Same thing for these data. > > Is there any thing wrong? > > Your suggestions are welcomed. > > > > Thank you in advance for your help! > > > > Regards, > > > > ME > > University of Houston > > > > > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://www.democritos.it/mailman/listinfo/pw_forum > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -------------- next part -------------- An HTML attachment was scrubbed... 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