[DFTB-Plus-User] treatment of edge dangling bonds

[Reinaldo Pis Diez]

Hi Robyn,

As Bálint says, the program does not make any special treatment of 
dangling bonds as far as I know.

You should saturate carbon atoms at the edges with hydrogen atoms in 
such a way that all carbons are formally sp^2. Some authors put the 
hydrogens at the usual equilibrium C-H distance, but others prefer 
to build shorter C-H distances to push the bonding combination well 
below the Fermi energy and the anti-bonding combination well above 
E_F. Thus, you avoid such "strange" states to go around the 
HOMO-LUMO gap.

Hope this helps.

Regards,

Reinaldo

On 07/06/2012 09:41 AM, Bálint Aradi wrote:
> Dear Robyn,
>
>> might I ask a question about the treatment of edge dangling bonds of 2D
>> graphene in DFTB calculation? if the edge is not terminated. Many thanks.
>
>   There are no special treatments for the edges, they are calculated
> "normally" as everthing else in the system. But I am not 100% sure,
> whether I understood your question.
>
>    Cheers,
>
>     Bálint
>
>
>
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