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[matthieu verstraete <matthieu.jean.verstraete@gmail.com>]

your 2 extra atoms are much too close to the first two. They need to
be spaced by the old lattice vector (0 0.5 0.5)*10.18 bohr

Matthieu

On Mon, Jul 13, 2009 at 9:39 PM, Purnaansh P
Gunaicha<purnaanshg@gmail.com> wrote:
> Hi Forum,
>
> I did a total energy run for diamond structure of silicon. It gave me an
> answer. But when i tried to do a similar run by increasing the number of
> atoms then instead of doubling the energy it gave me an answer which was ten
> time bigger then the first run. Down are the input files for the runs.
> Kindly go through them and provide corrections.
>
> 2atom_diamond structure of silicon
>
> Input
>
> acell  10.18 10.18 10.18
> rprim
> 0.0 0.5 0.5
> 0.5 0.0 0.5
> 0.5 0.5 0.0
> ntypat 1
> znucl 14
> natom 2
> typat 1 1
> xcart
>    0.00000000000000 0.00000000000000 0.00000000000000
>    0.47243153124000 0.47243153124000 0.47243153124000
> ecut  6.0
> kptopt 1
> ngkpt 8 8 8
> nstep 10
> toldfe 1.0d-8
> diemac 12.0
> Output
>
>  Components of total free energy (in Hartree) :
>     Kinetic energy  =  4.36994139614221E+00
>     Hartree energy  =  1.63067519413275E+00
>     XC energy       = -4.14284205020298E+00
>     Ewald energy    =  5.22656127763713E+00
>     PspCore energy  =  8.69853998679169E-02
>     Loc. psp. energy= -8.41405033073916E+00
>     NL   psp  energy=  4.23463483421105E+00
>     >>>>>>>>> Etotal=  2.99190572104891E+00
>  Other information on the energy :
>     Total energy(eV)=  8.14138950483921E+01 ;
>     Band energy (Ha)=  -3.8005471315E-01
>
> 4atom_diamond structure of silicon
>
> Input
>
> acell  10.18 10.18 10.18
> rprim
> 0.0 1.0 1.0
> 0.5 0.0 0.5
> 0.5 0.5 0.0
> ntypat 1
> znucl 14
> natom 4
> typat 1 1 1 1
> xcart
>    0.00000000000000 0.00000000000000 0.00000000000000
>    0.47243153124000 0.47243153124000 0.47243153124000
>    0.00000000000000 0.94486306249679 0.94486306249679
>    0.47243153124839 1.41729459374519 1.41729459374519
> ecut  6.0
> kptopt 1
> ngkpt 8 8 4
> nstep 20
> toldfe 1.0d-8
> diemac 12.0
> Output
>
> Components of total free energy (in Hartree) :
>     Kinetic energy  =  1.91724843402450E+01
>     Hartree energy  =  2.15989723059174E+01
>     XC energy       = -1.06573757754708E+01
>     Ewald energy    =  5.08787961524851E+01
>     PspCore energy  =  1.73970799735834E-01
>     Loc. psp. energy= -6.68898326663691E+01
>     NL   psp  energy=  1.19449362248025E+01
>     >>>>>>>>> Etotal=  2.62219513813459E+01
>  Other information on the energy :
>     Total energy(eV)=  7.13535584596061E+02 ;
>     Band energy (Ha)=  -2.7529499134E+00
> Also, the enrgies are positive which does not make sense. Kindly provide the
> relevant help.
>
> Thank you
> Purnaansh Gunaicha



-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dr. Matthieu Verstraete

European Theoretical Spectroscopy Facility (ETSF)
Dpto. Fisica de Materiales,
U. del Pais Vasco,
Centro Joxe Mari Korta, Av. de Tolosa, 72,   Phone: +34-943018393
E-20018 Donostia-San Sebastian, Spain        Fax  : +34-943018390

Mail : matthieu.jean.verstraete@gmail.com
http://www-users.york.ac.uk/~mjv500