The ABINIT Users Mailing List ( CLOSED )

["Nuno A. G. Bandeira" <nuno.bandeira@ist.utl.pt>]

Hello all,

I've been trying to optimise the unit cell of a polymer and I've set up 
a supercell model to do it.

The problem is abinis creates a lot of FFT grids because the supercell 
is large. I tried to change them with the ngfft key to speed up the 
calculations but the program won't parse this key and will keep running 
a 216 point fft grid no matter what.

Is this a problem or am I doing something wrong ? I'm sending the input 
attached.

I'd appreciate any advice you'd care to give.

--
                     Nuno A. G. Bandeira, AMRSC
           Graduate researcher and molecular sculptor
   Theoretical and Inorganic Chemistry Group, Faculty of Science
                       University of Lisbon
      C8 building, Campo Grande, 1749-016 Lisbon, Portugal
                   Doctoral student @ IST,Lisbon
======================================================================
Osbipy.in
Osbipy.out
Osbipy1
Osbipy2
Osbipy3
./Psps_for_tests/Os.fhi
./Psps_for_tests/N.fhi
./Psps_for_tests/C.fhi
./Psps_for_tests/H.fhi
./Psps_for_tests/O.fhi

#Definition of the unit cell
acell 20 5.75 20 angstrom

#Definition of the atom types
ntypat 5          # There is only one type of atom
znucl 76 7 6 1 8  # The keyword "znucl" refers to the atomic number of the
                  # possible type(s) of atom. The pseudopotential(s)
                  # mentioned in the "files" file must correspond
                  # to the type(s) of atom. Here, the only type is Hydrogen.

#Definition of the atoms
natom 50          # There are 50 atoms
typat 1 4 3 3 3 3 3 2 4 4 4 4 3 3 3 3 4 4 3 5 3 5 2 4 3 1 4 3 3 3 3 3 2 4 4 4 
4 3 3 3 3 4 4 3 5 3 5 2 4 3
xangst
     0.0000000       0.0000000       0.00000000
     -1.1468700      0.0000000       5.04067000
     -1.5605500      0.0000000       4.03715000
     -2.7043300      0.0000000       1.46481000
     -0.7302000      0.0000000       2.91263000
     -2.9513100      0.0000000       3.88378000
     -3.5243900      0.0000000       2.60963000
     -1.3337300      0.0000000       1.65161000
     -3.5910700      0.0000000       4.76327000
     -4.6067100      0.0000000       2.50191000
     -3.1538300      0.0000000       0.47073000
     1.1468700       0.0000000       5.04067000
     1.5605500       0.0000000       4.03715000
     0.7302000       0.0000000       2.91263000
     2.9513100       0.0000000       3.88378000
     3.5243900       0.0000000       2.60963000
     3.5910700       0.0000000       4.76327000
     4.6067100       0.0000000       2.50191000
     1.3050700       0.0000000       -1.61693000
     2.0281900       0.0000000       -2.51117000
     -1.3050700      0.0000000       -1.61693000
     -2.0281900      0.0000000       -2.51117000
     1.3337300       0.0000000       1.65161000
     3.1538300       0.0000000       0.47073000
     2.7043300       0.0000000       1.46481000
     0.0000000       2.8750000       0.0000000
     1.1468700       2.8750000       -5.0406700
     1.5605500       2.8750000       -4.0371500
     2.7043300       2.8750000       -1.4648100
     0.7302000       2.8750000       -2.9126300
     2.9513100       2.8750000       -3.8837800
     3.5243900       2.8750000       -2.6096300
     1.3337300       2.8750000       -1.6516100
     3.5910700       2.8750000       -4.7632700
     4.6067100       2.8750000       -2.5019100
     3.1538300       2.8750000       -0.4707300
     -1.1468700      2.8750000       -5.0406700
     -1.5605500      2.8750000       -4.0371500
     -0.7302000      2.8750000       -2.9126300
     -2.9513100      2.8750000       -3.8837800
     -3.5243900      2.8750000       -2.6096300
     -3.5910700      2.8750000       -4.7632700
     -4.6067100      2.8750000       -2.5019100
     -1.3050700      2.8750000       1.6169300
     -2.0281900      2.8750000       2.5111700
     1.3050700       2.8750000       1.6169300
     2.0281900       2.8750000       2.5111700
     -1.3337300      2.8750000       -1.6516100
     -3.1538300      2.8750000       -0.4707300
     -2.7043300      2.8750000       -1.4648100

#Definition of the planewave basis set
ecut 30           # Maximal plane-wave kinetic energy cut-off, in Hartree
ixc 11            # RPBE
chkprim 0
mkmem 0
mffmem 0
iscf 3
ntime 20

#Definition of the k-point grid
kptopt 1
#ngkpt 1 60 1
ngfft 48 72 48
optcell 5
ionmov 2
prtden 1
prtgeo 1
dilatmx 1.1
ecutsm 0.5

#Definition of the SCF procedure
nstep 200         # Maximal number of SCF cycles
toldfe 1.0d-5