Dear QE users My system has 54 atoms with a BCC structure. Its primitive unit cell includes 27 atoms. I am trying to find its lattice constant by using vc-relax. After running it several times and for more than 3 weeks still the convergence thresholds are not satisfied. The forces don't like to get smaller than a specific value (around 0.02). Is something wrong with my input file? Please let me know your comments.
Best regards,Payam Norouzzadeh &CONTROL title = Eight, calculation = "vc-relax", restart_mode = 'from_scratch' , prefix = "Eight", pseudo_dir = "/...", wfcdir = '...' , outdir = '/...', nstep = 100 , etot_conv_thr = 1.0E-9 , forc_conv_thr = 5.0D-5 , max_seconds = 172800 , dt = 100 , / &SYSTEM ibrav = 3, celldm(1)=19.622, nat = 27, ntyp = 3, ecutwfc = 70.D0, ecutrho = 700.D0, occupations='smearing', smearing='gaussian', degauss=0.02, / &ELECTRONS diagonalization = 'cg', conv_thr = 1.D-9, mixing_beta = 0.5D0, / &IONS ion_dynamics = 'damp' , / &CELL cell_dynamics = 'damp-w', / ATOMIC_SPECIES Al 26.98154 Al.pw91-n-van.UPF Si 28.0855 Si.pw91-n-van.UPF Ba 137.327 Ba.pw91-nsp-van.UPF ATOMIC_POSITIONS crystal Al 0.216201457 0.378180997 0.237078143 Al 0.034697037 0.023737131 0.761262755 Al 0.547173316 0.281036341 0.747383956 Al 0.499243974 0.592176706 0.241711510 Al 0.079436185 0.571961647 0.770077147 Al 0.696760320 0.247074460 0.186155320 Al 0.763858042 0.534829188 0.108400015 Si -0.084375501 0.661831874 -0.052015722 Si 0.768579606 0.003812573 0.065138231 Si 0.015665804 -0.146726664 0.029763195 Si 0.219167074 0.647981279 0.510896217 Si 0.688206047 0.299356062 0.551238353 Si 0.813578233 0.574824765 0.373099840 Si 0.455287149 0.559729400 0.815079368 Si 0.236709112 0.370770979 0.535759218 Si -0.101920499 0.795055135 0.400098065 Si 0.540358072 0.119760142 0.526376973 Si 0.817782198 0.005623765 0.511008919 Si 0.260966498 0.808368895 0.269851937 Si 0.611991634 -0.079635051 0.839306911 Si 0.368449934 0.463356223 0.046445257 Si 0.051075029 0.331552898 0.665912314 Si 0.416741872 0.793935246 -0.103728118 Ba 0.635745128 0.714712066 0.579828902 Ba 0.158096139 0.054209356 0.465675155 Ba -0.077117796 0.267386792 -0.044545628 Ba 0.416141346 0.060760806 0.081304511 K_POINTS automatic 6 6 6 0 0 0 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120307/41a9acbc/attachment.htm
