QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Shan on September 27, 2014, 09:15

Title: optical properties of Si tutorial (doubt)
Post by: Shan on September 27, 2014, 09:15

Hi,
I got a doubt while calculating the optical spectrum of Si,

In the tutorial it was given, from "script generator" send to "Editor", then find the line

 basis_set = [ LDABasis.DoubleZetaDoublePolarized, ]
                 and change this to
basis_set = [BasisGGAPBEHGH.Silicon_4_Tier_3, ]


Here my doubt is what does 4 and tier_3 indicates in the changed line; what should i write in place of 4_Tier_3 if i do the same calculations for Boron or antimony.


Thank you in advance.

Title: Re: optical properties of Si tutorial (doubt)
Post by: Anders Blom on September 27, 2014, 22:47

You can't figure that out in a logical way. The 4 here means the number of valence electrons, which depends on the pseudopotential. So it will be 5 (for Sb) if you continue using HGH pseudopotentials, but for the OMX ones introduced in 2014, the valence is 13 - it's a semicore potenital. So, use the Script Generator to set it up, and it will show you the available choices and generate the correct basis set notation for each element/pseudopotential.

Oh, I see this tutorial was probably written before we had support for the HGH basis sets in the Script Generator. So, simply put, if you use a newer version of ATK (13.8 or the latest 2014) you don't need to edit this manually, you can set it all up in the GUI. We'll update the tutorial!