[Pw_forum] Question about geometry relaxation

Юля Филичева djulriya at mail.ru
Wed Jul 27 13:46:06 CEST 2011


Dear QE users,

I'm a new user of QE.
Now I try to provide the geometry relaxation of carbon diamond-like structure, but I'm not sure that I'm doing it right.
It would be kind of you, if you advise me what type of optimizer or some parameters which I don't use here should I use to achieve the best results?
Below I will give an example of my input file.

 &control
    calculation = 'vc-relax'
    restart_mode='from_scratch',
    prefix='carbon',
    tstress = .true.
    tprnfor = .true.
    pseudo_dir = './',
    outdir='./'
wf_collect=.true.,
etot_conv_thr = 1.0D-6,
forc_conv_thr = 1.0D-4,
nstep = 500,

 /
 &system
                     nosym = .false.,
                     ibrav = 1,
                     celldm(1) = 8.0907,
                     nat = 16,
                     ntyp = 1,
                     occupations = 'smearing',
             ecutwfc = 60,
             degauss = 0.05,
 /
 &ELECTRONS
               diagonalization = 'cg' ,
               electron_maxstep = 150,
 /
 &IONS
  ion_dynamics='bfgs',
  pot_extrapolation = "first_order",
 /
 &CELL
   cell_dynamics = 'bfgs' ,
   cell_factor = 1.6,
   press = 0 ,
   !cell_dofree = 'xyz',
press_conv_thr = 0.5D-1, 
 /
ATOMIC_SPECIES
 C    12    C.pbe-van_ak.UPF
ATOMIC_POSITIONS crystal
...
K_POINTS automatic 
 8 8 8  0 0 0


Thank you in advice.
Sincerely yours
Julia Filicheva


/First year of master degree study
Moscow Institute of Physics and Technology/


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