[Pw_forum] Defining 1-D Graphene Nanoribbon

swapnil chandratre swapnil.chandratre at gmail.com
Sun Jun 5 22:43:06 CEST 2011


Hi,

I define the graphene ribbon(1-D), periodic in z direction by



 /
 &system

    ibrav = 0

nat=60
ntyp=2
ecutwfc=50.0
ecutrho = 600.0
,
 /
 &electrons
    conv_thr = 1.0d-6,
    mixing_beta=0.05,
  /

ATOMIC_SPECIES
C 12.0000 C.pz-rrkjus.UPF
H 1.00000 H.pz-rrkjus.UPF

ATOMIC_POSITIONS {angstrom}
   C   5.000000e+00  6.005391e+00  2.864597e+00
  C   5.000000e+00  7.195584e+00  3.619975e+00
  C   5.000000e+00  6.005370e+00  1.482985e+00
  C   5.000000e+00  8.420899e+00  2.896093e+00
  C   5.000000e+00  9.650820e+00  3.625321e+00
  C   5.000000e+00  7.195533e+00  7.276090e-01
  C   5.000000e+00  8.420864e+00  1.451361e+00
  C   5.000000e+00  1.086968e+01  2.895976e+00
  C   5.000000e+00  1.209962e+01  3.625208e+00
  C   5.000000e+00  9.650806e+00  7.222413e-01
  C   5.000000e+00  1.086970e+01  1.451465e+00
  C   5.000000e+00  1.332495e+01  2.901401e+00
  C   5.000000e+00  1.451503e+01  3.657009e+00
  C   5.000000e+00  1.209965e+01  7.223490e-01
  C   5.000000e+00  1.332498e+01  1.446149e+00
  C   5.000000e+00  1.451517e+01  6.907900e-01
  H   5.000000e+00  5.029452e+00  3.377799e+00
  H   5.000000e+00  5.029415e+00  9.698360e-01
  H   5.000000e+00  1.549104e+01  3.143928e+00
  H   5.000000e+00  1.549109e+01  1.204033e+00
  C   5.000000e+00  6.005518e+00  7.212533e+00
  C   5.000000e+00  7.195603e+00  7.968203e+00
  C   5.000000e+00  6.005518e+00  5.830967e+00
  C   5.000000e+00  8.420899e+00  7.244204e+00
  C   5.000000e+00  9.650813e+00  7.973587e+00
  C   5.000000e+00  7.195603e+00  5.075297e+00
  C   5.000000e+00  8.420899e+00  5.799296e+00
  C   5.000000e+00  1.086964e+01  7.244085e+00
  C   5.000000e+00  1.209955e+01  7.973476e+00
  C   5.000000e+00  9.650813e+00  5.069913e+00
  C   5.000000e+00  1.086964e+01  5.799415e+00
  C   5.000000e+00  1.332483e+01  7.249443e+00
  C   5.000000e+00  1.451500e+01  8.004905e+00
  C   5.000000e+00  1.209955e+01  5.070024e+00
  C   5.000000e+00  1.332483e+01  5.794057e+00
  C   5.000000e+00  1.451500e+01  5.038595e+00
  H   5.000000e+00  5.029453e+00  7.725544e+00
  H   5.000000e+00  5.029453e+00  5.317956e+00
  H   5.000000e+00  1.549104e+01  7.491852e+00
  H   5.000000e+00  1.549104e+01  5.551648e+00
  C   5.000000e+00  6.005370e+00  1.156051e+01
  C   5.000000e+00  7.195533e+00  1.231589e+01
  C   5.000000e+00  6.005391e+00  1.017890e+01
  C   5.000000e+00  8.420864e+00  1.159214e+01
  C   5.000000e+00  9.650806e+00  1.232126e+01
  C   5.000000e+00  7.195584e+00  9.423525e+00
  C   5.000000e+00  8.420899e+00  1.014741e+01
  C   5.000000e+00  1.086970e+01  1.159203e+01
  C   5.000000e+00  1.209965e+01  1.232115e+01
  C   5.000000e+00  9.650820e+00  9.418179e+00
  C   5.000000e+00  1.086968e+01  1.014752e+01
  C   5.000000e+00  1.332498e+01  1.159735e+01
  C   5.000000e+00  1.451517e+01  1.235271e+01
  C   5.000000e+00  1.209962e+01  9.418292e+00
  C   5.000000e+00  1.332495e+01  1.014210e+01
  C   5.000000e+00  1.451503e+01  9.386491e+00
  H   5.000000e+00  5.029415e+00  1.207366e+01
  H   5.000000e+00  5.029452e+00  9.665701e+00
  H   5.000000e+00  1.549109e+01  1.183947e+01
  H   5.000000e+00  1.549104e+01  9.899572e+00


CELL_PARAMETERS
20.000000 0.000000 0.0000000
0.0000000 45.96300 0.0000000
0.0000000 0.000000 24.648513

K_POINTS {automatic}
1 1 24  0 0 0


, the output file gives the following data
Parallel version (MPI), running on    24 processors
     R & G space division:  proc/pool =   24

     Current dimensions of program PWSCF are:
     Max number of different atomic species (ntypx) = 10
     Max number of k-points (npk) =  40000
     Max angular momentum in pseudopotentials (lmaxx) =  3
     Waiting for input...
     file C.pz-rrkjus.UPF: wavefunction(s)  2S renormalized
     file H.pz-rrkjus.UPF: wavefunction(s)  1S renormalized

     Subspace diagonalization in iterative solution of the eigenvalue
problem:
     parallel, distributed-memory algorithm (size of sub-group:  3*  3
procs)

     warning: symmetry operation #  3 not allowed.   fractional translation:
       0.0551369  0.0000000 -0.0000050  in crystal coordinates
     warning: symmetry operation #  8 not allowed.   fractional translation:
       0.0551369  0.0000000  0.0000000  in crystal coordinates

   Stick Mesh
   ----------
   nst = 43869,  nstw =  3781, nsts = 14625
               n.st   n.stw   n.sts    n.g    n.gw   n.gs
   min        1827     157     609  234299    5945   45073
   max        1828     159     610  234302    5948   45104
      43869    3781   14625 5623217  142709 1082119



     bravais-lattice index     =            0
     lattice parameter (a_0)   =      20.0000  a.u.
     unit-cell volume          =   22658.3921 (a.u.)^3
     number of atoms/cell      =           60
     number of atomic types    =            2
     number of electrons       =       204.00
     number of Kohn-Sham states=          102
     kinetic-energy cutoff     =      50.0000  Ry
     charge density cutoff     =     600.0000  Ry
     convergence threshold     =      1.0E-06
     mixing beta               =       0.0500
     number of iterations used =            8  plain     mixing
     Exchange-correlation      =  SLA  PZ   NOGX NOGC (1100)
     EXX-fraction              =        0.00

     celldm(1)=  20.000000  celldm(2)=   0.000000  celldm(3)=   0.000000
     celldm(4)=   0.000000  celldm(5)=   0.000000  celldm(6)=   0.000000

     crystal axes: (cart. coord. in units of a_0)
               a(1) = (   1.000000   0.000000   0.000000 )
               a(2) = (   0.000000   2.298150   0.000000 )
               a(3) = (   0.000000   0.000000   1.232426 )

     reciprocal axes: (cart. coord. in units 2 pi/a_0)
               b(1) = (  1.000000  0.000000  0.000000 )
               b(2) = (  0.000000  0.435133  0.000000 )
               b(3) = (  0.000000  0.000000  0.811408 )


Am I making any mistake anywhere (considering a0=20,and celldm(3)=0 ), does
it define 1-D , z periodic structure) ? , my box is orthorhombic, so should
I specifically use ibrav and celldm instead of defining the cell parameters
?



-- 
Regards,
Swapnil Chandratre
Graduate Student
Dept. of Mechanical Engineering,
University of Houston,
Houston, TX
(M)-713-294-9546
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