[DFTB-Plus-User] HOMO-LUMO gap in rectangular quantum dots

[SRKC Sharma Yamijala]

Hi,
Can anybody comment on the above mail?

Thanks,
Sincerely,
Sharma.








********************************************************
*Chaitanya Sharma,*
*Prof. Pati'*s group,
Chemistry and Physics Materials unit,
JNCASR, BANGLORE,
Lab:: (080-2208) 2581, 2809
https://sites.google.com/site/sharmasrkcyamijala/
*********************************************************

On Wed, Apr 15, 2015 at 5:18 PM, SRKC Sharma Yamijala <
sharmajncasr at gmail.com> wrote:

> Dear all,
>
> I have optimized a rectangular Graphene quantum dot in both SIESTA (PBE
> functional) and DFTB+. I got the HOMO-LUMO gap to be ~ 0.5 eV using SIESTA
> and ~ 0 eV using DFTB+ (even from the SIESTA optimized coordinates).
>
> I have also tried with simple tight-binding code (only hopping considered)
> with t=2.8 and I got the similar result as that of DFTB+ (~0 eV HOMO-LUMO
> gap).
>
> Is there a way, I can reproduce the SIESTA HOMO-LUMO gap using DFTB+?
>
> Final coordinates and the input for DFTB+, SIESTA are attached.
>
> geom.out.xyz is from DFTB+ and zgnr_C_8_308.xyz is from SIESTA.
>
> Thanks,
> Sincerely,
> Sharma.
>
>
> ********************************************************
> *Chaitanya Sharma,*
> *Prof. Pati'*s group,
> Chemistry and Physics Materials unit,
> JNCASR, BANGLORE,
> Lab:: (080-2208) 2581, 2809
> https://sites.google.com/site/sharmasrkcyamijala/
> *********************************************************
>
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