Dear Paolo Giannozzi, Thanks for your reply and useful files. I have used 'vdw-df' to correct to PBE functional in bilayer graphene, and get good results (3.40 angstrom). Some tips should be noted. One should not provide a primitive structure with large deviation from equilibrium, e.g, 5.0 angstorm for layer-distance is bad guess. On the other hand, I think of 'vdw-df' as a correction for LDA meaningless although it gives somelike results. Because this kind of correction is added for GGA. So, I want to konw whether my second opition is right? BTW, I also donnot understand why you set 'input_dft='Pz' but with PBE fubction.
Best wishes P. L. Gong > -----原始邮件----- > 发件人: "Paolo Giannozzi" <[email protected]> > 发送时间: 2014年10月17日 星期五 > 收件人: "PWSCF Forum" <[email protected]> > 抄送: > 主题: Re: [Pw_forum] vdw correction for Bi-layer grahene > > Please see some slides and an example (graphite) here: > http://www.fisica.uniud.it/~giannozz/Public/vdw.tar.gz > P. > > On Fri, 2014-10-17 at 18:56 +0800, plgong wrote: > > Dear pwscf user, > > Recently, I calculated Bilayer graphene with vdw correction. In version > > of 4.3, the parameter of London can be set to 'true' > > and then add vdw correction to Exc. In version of 5.1, more options can do > > it, such as, 'grimmer-d2', 'dft-d'. However, many tests have been performed > > but I cannot get the layer-distance (3.34 angstrom in experiment). I uesd > > GGA-PBE and LDA-PZ with vdw, recepetively. The final results shows small > > distance (3.0 angstrom). I donnot know why leads to the small distance. > > So, I still tested the Ecut (30Ry-60Ry0) and vaccum (10-20 angstrom), but > > the problem was the same. > > The input file is, > > > > &CONTROL > > calculation = 'relax' , > > outdir ='./tmp' , > > restart_mode = 'from_scratch' , > > pseudo_dir ='/home/plgong/pseudo', > > etot_conv_thr = 1.0e-4 , > > forc_conv_thr = 1.0e-3 , > > prefix='graphene', > > / > > &SYSTEM > > ibrav = 4, > > a =2.46 > > c =10.0 > > nat = 4, > > ntyp = 1, > > ecutwfc = 30.D0 , > > ecutrho = 240.0 , > > vdw_corr='grimme-d2' > > tot_charge = 0.00, > > occupations = 'smearing' , > > degauss = 0.02 , > > smearing='mv' > > > > / > > &ELECTRONS > > conv_thr = 1.D-7 , > > mixing_beta=0.3 > > mixing_mode='local-TF' > > electron_maxstep=300 > > / > > &IONS > > ion_dynamics = 'bfgs' , > > > > / > > ATOMIC_SPECIES > > C 12.00000 C.pz-rrkjus.UPF > > ATOMIC_POSITIONS {crystal} > > C 0.000000 0.000000 0.500000 > > C 0.333333 0.666667 0.500000 > > C 0.000000 0.000000 0.834000 > > C 0.666667 0.333333 0.834000 > > K_POINTS {automatic} > > 30 30 1 0 0 0 > > > > Can anyone help me to solve it? > > > > P. L. Gong > > ISSP CAS, HeFei, China > > > > > > > > -- > > > > ==================================================== > > Addr: Institute of Solid State Physics, Chinese Academy of > > Sciences, Hefei, Anhui 230031, China > > Tel: +86-551-65591591(office), 18756086113(cell phone) > > Email: [email protected] > > ======================================================================== > > > > > > > > > > > > _______________________________________________ > > Pw_forum mailing list > > [email protected] > > http://pwscf.org/mailman/listinfo/pw_forum > > -- > Paolo Giannozzi, Dept. Chemistry&Physics&Environment, > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- ==================================================== Addr: Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China Tel: +86-551-65591591(office), 18756086113(cell phone) Email: [email protected] ======================================================================== _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
