QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: NW on November 26, 2018, 17:50

Title: Electron occupation
Post by: NW on November 26, 2018, 17:50

Hello,

Can I obtain the electron occupation for each orbitals in ATK? If yes, how?
Thanks

Title: Re: Electron occupation
Post by: Daniele Stradi on November 27, 2018, 09:20

Hi,

one solution could be to use Mulliken population analysis:
https://docs.quantumwise.com/manual/Types/MullikenPopulation/MullikenPopulation.html

Best regards,
Daniele

Title: Re: Electron occupation
Post by: NW on December 10, 2018, 17:17

I obtained Mulliken population as attached file. I cannot understand why there are 4 electrons (spin.up+spin.down) for each carbon atoms. It seems to be 6. Also, for each C atom there are 5 lines for each spin (two S, two P and one d). What are these S belong to? 1s or 2s or 3s?

Title: Re: Electron occupation
Post by: Ulrik G. Vej-Hansen on December 11, 2018, 09:09

I assume you have used a pseudopotential with 2 electrons in the core, such as the default PseudoDojo. In that case, they are not counted in the analysis.

In a Mulliken Population analysis, the electron density is projected onto the basis functions, so if you have used the PseudoDojo-Medium basis set, there are two 2s-like orbitals, two 2p-like orbitals and one 3d-like orbital. Note that the populations are quite small on the second and fourth basis functions, as they are not the primary basis functions for describing that orbital.

Title: Re: Electron occupation
Post by: NW on December 18, 2018, 13:12

I used OMX medium basis set.
Is it a good choice to use OMX or SG15 to obtain Mulliken population?

Title: Re: Electron occupation
Post by: Daniele Stradi on December 18, 2018, 13:17

Yes, it is a good choice.