[DFTB-Plus-User] electric field in DFTB

[Ben Hourahine]

On 11/08/10 03:13, manuelel at libero.it wrote:
> dear all
>
> I'm new to DFTB+ and Tight binding (TB) theory in general.
> I'd like to know how the interaction of point charges (as included via the "ElectricField  = { PointCharges" keyword in an SCC run) with the TB wavefunction is taken into account. In particular if the charges are directly included in the Self Consistent part of the calculation (an so polarize the TB Wave function) or if it is evaluated a posteriori as the elctrostatic interaction of the charge density with the point charges.
>
> thank you in advance
> Manuele Lamarra
>
>
>
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Hello Manuele,

Currently DFTB+ only allows external electric fields when they are
included within the total potential in a self-consistent calculation. 
Hence the
resulting SCC TB wavefunction is the ground state of system in the external
potential due to the applied field (either point charges, or also a 
specified electric
field if using non-periodic boundary conditions).

There are some more details on how this potential is added to the 
Hamiltonian
in this recent paper:

http://dx.doi.org/10.1088/1742-6596/242/1/012005

Let me know if you need more details.

Regards

Ben

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      Dr. B. Hourahine, SUPA, Department of Physics,
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