Hi, Presumably, you should use more k-points, and may be larger cutof energy. More accurate calculations (conv_thr) also might help.
Bests, Eyvaz --- XunLei Ding <dxl at ustc.edu.cn> wrote: > Dear all, > I do a calculation to get the lattice constant of Ni > crystal. > I scan the lattice constant from 6.60 to 6.70 a.u. > using the bash file below. > The experimental value is 6.66 and is consistent > with my result. > But it is clear that the curve departs into two > parts at 6.66. > (see the picture at > http://www.bsc.ustc.edu.cn/~dxl/download/Graph1.JPG) > Would you tell my why and how to solve this problem. > > Thank you! > > Ding Xunlei > > for a0 in 6.60 6.61 6.62 6.63 6.64 6.65 6.66 6.67 > 6.68 6.69 6.70 > do > cat >test.in<<! > &control > calculation='scf' > restart_mode='from_scratch', > pseudo_dir = '/home/bsc/dxl/pseudo/', > outdir='./' > prefix='zz' > tprnfor = .true., > for a0 in 6.64 > do > cat >test.in<<! > &control > calculation='scf' > for a0 in 6.65 > do > cat >test.in<<! > &control > calculation='scf' > restart_mode='from_scratch', > pseudo_dir = '/home/bsc/dxl/pseudo/', > outdir='./' > prefix='zz' > tprnfor = .true., > tstress = .true. > / > &system > ibrav=2, celldm(1) =$a0 > nat=1,ntyp=1, > nspin = 2, starting_magnetization(1)=0.7, > ecutwfc = 24.0, ecutrho = 288.0, > occupations='smearing', > smearing='methfessel-paxton', degauss=0.01 > / > &electrons > electron_maxstep= 200 > diagonalization='' > conv_thr = 1.0e-8 > mixing_beta = 0.2 > &cell > cell_dynamics = 'none' > cell_factor = 1.2 > / > &ions > ion_dynamics = 'damp' > > / > ATOMIC_SPECIES > Ni 58.69 Ni.pbe-nd-rrkjus.UPF > ATOMIC_POSITIONS > Ni 0.00000000 0.000000000 0.000000000 1 > 1 1 > K_POINTS (automatic) > 13 13 13 1 1 1 > ! > > > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > ______________________________________________________ Click here to donate to the Hurricane Katrina relief effort. http://store.yahoo.com/redcross-donate3/
