what's wrong? why don't you use non-zero gaussian spreading? The purpose of using smearing is to avoid a step function at Fermi level. If the system is metallic, gaussian spreading must be non-zero. If it is not metallic, a non-zero gaussion spreading won't harm your calculation. -------------------------------------------------- Duy Le PhD Student Department of Physics University of Central Florida.
"Men don't need hand to do things" On Fri, Aug 27, 2010 at 3:29 PM, chengyu yang <chengyu.young at gmail.com> wrote: > Dear all, > ????????? If I have a copper/carbon nanotube system, and the nanotube is > semiconducting, what value should the degauss be ?Is it still a metallic > system? I used the degauss as 0,but it was wrong. I'm a little confused. > ?thank you. > > &CONTROL > ???????????????? calculation = 'scf' , > ??????????????? restart_mode = 'from_scratch' , > ?????????????????????? prefix = '22' , > ?/ > ?&SYSTEM > ?????????????????????? ibrav = 6,celldm(1) = 21.764541128,celldm(3)=0. > 213765379 > ???????????????????????? nat = 10,ntyp = 2,ecutwfc = 75 , > ???????????????????? occupations='smearing', smearing='gaussian', degauss=0 > ?/ > &ELECTRONS > ??????????????????? conv_thr = 1.0d-8 , > ???????????????? mixing_beta = 0.7 , > ?/ > ATOMIC_SPECIES > ??? C?? 12.01100? C.pz-vbc.UPF > ??? Cu? 63.55???? Cu.pz-d-rrkjus.UPF > > ATOMIC_POSITIONS angstrom > ? C??????? 1.402181??? -0.000000??? -1.233916 > ? C??????? 0.682146???? 1.225067??? -1.233916 > ? C?????? -0.000000???? 1.402181??? -0.000000 > ? C?????? -1.225067???? 0.682146??? -0.000000 > ? C?????? -1.402181??? -0.000000??? -1.233916 > ? C?????? -0.682146??? -1.225067??? -1.233916 > ? C?????? -0.000000??? -1.402181??? -0.000000 > ? C??????? 1.225067??? -0.682146??? -0.000000 > ? Cu?????? 0??????????? 2.804362????? 0 > ? Cu????? -1.402181???? 2.428648737?? 0 > > > K_POINTS automatic > ??? 1 1 5 0 0 0 > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > >
