[Pw_forum] vc-relax

[Detlef Schmicker]

Hello,

I had some trouble reaching the list with my usual
e-mail adress, I try
this new one. (In case an list administrator reads
this, I can send the
error messages to him).

I try to do some calculations on BiSrCaCuO high
temperatur
superconductor. I am interested in the total one
electron potential in
the CuO planes, especialy with displaced O atoms
(optical phonon). 

To check the calculation, I calculated the forces, if
one displaces the
O atoms, and they were not quite good. Therefore I
wanted to vc-relax
the system. The input file therefore is appended. I
have limited
computational resources (2.4GHz Pentium). But it looks
to me (after
weeks of computations) that I do not get the forces
down. The total
force stays in the order of 0.02 Ry / au.

Do you have any hints, what I might do to further
relax the structure. I
used espresso 3.1.1 and 3.2

Thanks in advanced

Detlef Schmicker

 &CONTROL
                       title = 'dd3' ,
                 calculation = 'vc-relax' ,
                restart_mode = 'from_scratch' ,
                  wf_collect = .false. ,
                      outdir =
'/home/detlef/espresso-3.1.1/GUI/TMP/' ,
                  pseudo_dir = 'pseudo/' ,
                      prefix = 'htc11_optimized4444' ,
                     disk_io = 'default' ,
                   verbosity = 'default' ,
                     tstress = .true. ,
                     tprnfor = .true. ,
                          dt = 300 ,
                     tefield = .false. ,
                    lelfield = .false. ,
                      lberry = .false. ,
 /
 &SYSTEM
                       ibrav = 0,
                   celldm(1) = 7.2,
                         nat = 30,
                        ntyp = 5,
                     ecutwfc = 50 ,
                     ecutrho = 190 ,
                       nosym = .false. ,
                 occupations = 'smearing' ,
                     degauss = 0.05 ,
                    smearing = 'methfessel-paxton' ,
                       nspin = 1 ,
 /
 &ELECTRONS
                    conv_thr = 1.D-5 ,
                 mixing_beta = 0.1 ,
 /
 &IONS
                ion_dynamics = 'damp' ,
           pot_extrapolation = 'second_order' ,
           wfc_extrapolation = 'second_order' ,
 /
 &CELL
               cell_dynamics = 'damp-w' ,
                       press = 0 ,
                       wmass = 0.01 ,
 /
CELL_PARAMETERS cubic 
   0.962        0.000000000     0.000000000
   0.000000000  0.962           0.000000000
   0.000000000  0.000000000     8.44
ATOMIC_SPECIES
   Bi   50.00000  bi_ps.uspp.UPF 
   Sr   50.00000  sr_ps.uspp.UPF 
   Cu   50.00000  cu_ps.uspp.UPF 
    O   50.00000  o_ps.uspp.UPF 
   Ca   50.00000  ca_ps.uspp.UPF 
ATOMIC_POSITIONS crystal 
O        0.500000000   0.500000000   0.002837609
Bi       0.000000000   0.000000000   0.001569682
Sr       0.500000000   0.500000000   0.087756900
O        0.000000000   0.000000000   0.063826646
Cu      -0.000000000  -0.000000000   0.144249833
O       -0.000000000   0.500000000   0.140900561
O        0.500000000  -0.000000000   0.140900561
Ca       0.500000000   0.500000000   0.189456976
O        0.500000000  -0.000000000   0.237997150
O       -0.000000000   0.500000000   0.237997150
Cu       0.000000000   0.000000000   0.234681387
O       -0.000000000  -0.000000000   0.314954629
Sr       0.500000000   0.500000000   0.291099378
Bi      -0.000000000  -0.000000000   0.377190432
O        0.500000000   0.500000000   0.375992399
O        0.000000000   0.000000000   0.502390453
Bi       0.500000000   0.500000000   0.501105763
Sr       0.000000000   0.000000000   0.587341137
O        0.500000000   0.500000000   0.563374928
Cu       0.500000000   0.500000000   0.643872634
O        0.500000000  -0.000000000   0.640520966
O       -0.000000000   0.500000000   0.640520966
Ca      -0.000000000  -0.000000000   0.689096125
O       -0.000000000   0.500000000   0.737680424
O        0.500000000  -0.000000000   0.737680424
Cu       0.500000000   0.500000000   0.734346142
O        0.500000000   0.500000000   0.814758134
Sr      -0.000000000  -0.000000000   0.790802285
Bi       0.500000000   0.500000000   0.876909632
O       -0.000000000  -0.000000000   0.875824403
K_POINTS automatic 
  3 3 3   0 0 0 



		
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