[Pw_forum] Difference between cartesian coordinates and crystal coordinates

yumin qian yuminqian at gmail.com
Tue Apr 19 15:59:27 CEST 2011

Dear Pwscf user
       I am still do not very clear how to set the axes using crystal axes
in the &system  card
      ibrav  and celldm(:) define the gives the  cartesian coordinates
      ibarv and A, B,C, cosab, cosac,cosbc gives the crystal coordinates

is my understanding correct?
the following two cards are all coordinate dependent
there are either in accordence with cartesian coordinates or crystal
how to make the three cards are in the same coordinates forms? or there are
all independent and can work consistent with it self in either coordinates?
The mixture of unit(alat,borhr,angstrom) and coordinates(crystal ,cartesian
) often confuse me.

is there anyone tell me how to set the ( &system,ATOMIC_POSITIONS, K_POINTS)
for cartesian coordinates and crystal coordinates respectively

and this is my input file for crystal coordinates structure, it can not give
right symmetry, I do not know the reason.

    pseudo_dir = '/home1/ymqian/soft/pwscf/psudo',
    ibrav = 7, A=4.1105, B=4.1105, C=14.65253, cosAB=90, cosAC=90, cosBC=90
    , nat= 7, ntyp= 4,
    ecutwfc = 45.0, ecutrho = 400.0
    occupations='smearing', smearing='mv', degauss=0.02,
    conv_thr = 1.0e-7
    mixing_beta = 0.7
Na  22.98977  Na.pbe-sp-van_ak.UPF
Fe  55.845    Fe.pbe-sp-van.UPF
Se  78.96     Se.pbe-van.UPF
O   15.9994   O.pbe-van_ak.UPF
Na  0.500   0.500   0.1636801516544306
Na  0.000   0.000   0.3363198483455694
Fe  0.500   0.000   0.000000000000000
Fe  0.000   0.500   0.000000000000000
Se  0.000   0.000   0.1090917831789712
Se  0.500   0.500   0.3909082168210289
O   0.500   0.500   0.000000000000000
K_POINTS automatic
 12 12 4 0 0 0

Best Regards
Sincerely Y. M. Qian (钱玉敏)
Laboratory of Condensed Matter Theory and Materials Computation
Institute of Physics(IOP), Chinese Academy of Sciences(CAS)
Tel:        + 8610 8264 9827
E-Mail:    yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com>
P.O.Box 603   Beijing 100190
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