Dear Ney,
The system is organic crystal. You mean it cannot be calculated with
GGA?
2009/6/16 N H <neyh...@gmail.com>
> Well ...
>
> I dont have much information about your system ... Is it a molecule? Or a
> polymer maybe?
>
> Anyway ... I dont know if it makes much sense calculating organic solids
> with GGA. The solid state in such materials is highly dependent on
> dispersion interactions like van der walls and london forces, which are not
> described by GGA. Thus, I would not be suprised with large cell parameters
> in this cases. Some guys I know correct it by ading an empirical
> Lenard-Jones like potential in the system ... but ...it is something "ad
> hoc".
>
> Cheers
>
> Ney
>
>
>
> On Tue, Jun 16, 2009 at 10:40 AM, Sridhar Neelamraju <
> neelamraju.srid...@gmail.com> wrote:
>
>> I imagine siesta uses primitive (Wigner-Seitz)cell parameters whereas
>> experimentalists prefer crystallographic units. Could someone else confirm
>> the same please?
>>
>> 2009/6/16 samtong <zjx...@gmail.com>
>>
>> Deal all,
>>> Attached is the .fdf file.
>>> The Pseudopotencial and basis sets of C, H, O, N, S in the system are
>>> downloaded from siesta website. But the calculated lattice parameters are
>>> almost doubled than experimental value. Could anyone tell me where i am
>>> wrong? Thank u very much.
>>>
>>> Chales
>>>
>>
>>
>>
>> --
>> Sridhar Neelamraju
>> PhD Student, Jansen Group
>> Max-Planck-Institute for Solid State Chemistry
>> Stuttgart, Germany - 70569
>>
>> E-mail:s.neelamr...@fkf.mpg.de <e-mail%3as.neelamr...@fkf.mpg.de>
>> Landline: (+49)0711-12164749
>> Mobile: (+49) 0176-70128213
>>
>
>
