Can Yambo deal with systems with odd number of electrons?

[yunhailiseu]

Dear Yambo team,

Can yambo deal with systems with odd number of electrons? Or a more general question, can the DFT+GW+BSE procedure deal with odd number of electrons?

I know some sort of quamtum chemistry techniques. For odd-number of electrons, unrestricted Hartree-Fock method is essential. But I know little of the philosophy how DFT and GW/BSE deal with it.

Do I need spin-polarized calculations? Are there any special treatment?

Best,
Yubhai

[Daniele Varsano]

Dear Yunhai,
yes you need a spin-polarized calculation. The ground state can be calculated using quantum-espresso or abinit. Next, Yambo can do GW/BSE on top of it.
Best,
Daniele

[yunhailiseu]

Dear Yunhai,
yes you need a spin-polarized calculation. The ground state can be calculated using quantum-espresso or abinit. Next, Yambo can do GW/BSE on top of it.
Best,
Daniele

Daniele,

Thank you for the reply.

Since for odd-number of electrons the picture of singlet and tripet breaks down, how to deal with the BSE kernel? Does it contains both the exchange term and direct term?

Best,
Yunhai

[Daniele Varsano]

Dear Yunhai,
In this case, the BSE is solved directly in the spin space:
You can have a look to this post:

viewtopic.php?f=28&t=789&start=20#p3389

Best,

Daniele

[yunhailiseu]

Dear Yunhai,
In this case, the BSE is solved directly in the spin space:
You can have a look to this post:

viewtopic.php?f=28&t=789&start=20#p3389

Best,

Daniele

Ok, I will consult that post.

Best,
Yunhai