[Pw_forum] Query on Double numerical atomic orbitals

[Nicola Marzari]

Dear Ajit,


it's a completely different story - QE uses plane waves as a basis
set, and you just increase the cutoff to improve your basis convergence.

Other codes (quantum chemistry codes, SIESTA...) use atomic-like or 
gaussian-like localized basis sets; you need much fewer of these, but
convergence is much trickier.

You probably need to study a good book on electronic structure methods,
and/or some of the tutorials on the QE webpage, before doing much else.

				nicola



On 09/01/2014 05:23, Ajit Vallabhaneni wrote:
> Dear QE users,
>
>            I am new to QE and am trying to do some calculations on GNRs. In the literature i reviewed, it was mentioned that "double numerical atomic orbitals along with polarisation functions" were used as a basis for the tens of atoms in the unitcell. From the little i understood, the double radial functions lead to better accuracy and convergence. I was wondering if it is implemented by default in QE or not. Please let me know.
>
>


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Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL