[Pw_forum] convergence of relaxation caculation

[Axel Kohlmeyer]

On Fri, 1 Aug 2008, meisam aghtar wrote:


dear meisam,

please note, that you are using norm-conserving pseudopotentials
yet wavefunction and density cutoff parameters as if it were
ultra-soft potentials. this means your wavefunction cutoff is too
small and your density cutoff too large (no gain from going higher
than 4x ecutwfc). did you make any tests of those pseudopotentials?
e.g. on a small graphene sheet or a benzene/naphtaline molecule??

cheers,
   axel.

MA>  &SYSTEM
                       ibrav = 4,
                   celldm(1) = 32,
                   celldm(3) = 0.251568464,
                         nat = 80,
                        ntyp = 2,
                     ecutwfc = 36 ,
                     ecutrho = 400 ,
                        

[...]

    C   12.01070  C.pz-vbc.UPF 
    H    1.00794  H.vbc.UPF 




-- 
=======================================================================
Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.