pseudopotential-basis set

[xiaoteng]

Hi，
    When I begin an optimizegeometry, I choose pseudopotential :OMX. At this time, the basis set has several choices, such as Rc=7.0 Tier 0,Rc=7.0 Tier 1, Rc=9.0 Tier 0, Rc=9.0 Tier1, Rc=11.0 Tier 0, Rc=11.0 Tier1. I want to know the diffence among them and how to choose the appropriate one.
   Actually, I saw the tutorials from  QuantumWise Forum，and it shows that the basis set is medium[s2p2d1]. Why is it different from mine?

[Daniele Stradi]

Which version of ATK are you using?

[xiaoteng]

Virtual NanoLab 2014.3

[Petr Khomyakov]

See the following Forum discussion on this topic: http://quantumwise.com/forum/index.php?topic=3185.0. The ATK version you are using is quite old by now, whereas the tutorials refer to an up-to-date version of ATK.

[xiaoteng]

Thank you！
I have other question.
I will  calculate the band structure with SOC by choosing OMX pseudopotential. Before this, I need to optimise the structure. So I want to know which pseudopotential should I choose during the optimization, FHI or OMX?
And hope you can give me the link about the theoretical knowledge of OMX, FHI.

[Petr Khomyakov]

For the sake of consistency, I would stick to one pseudopotential for all the calculations, including geometry optimization.

You may read about pseudopotentials in the ATK at http://docs.quantumwise.com/technicalnotes/atk_pseudo_basis/atk_pseudo_basis.html, as well as following the links and references therein for having even more information on the pseudopotentials.

[xiaoteng]

Thank you so much！