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Yb_2 as the "recommended" pseudopotential

Posted: Tue Jan 25, 2022 10:08 am
by andrew_rosen
Hello,

On the VASP [wiki](https://www.vasp.at/wiki/index.php/Avai ... potentials), there is a list of "recommended" VASP .54 PAW PBE potentials. The recommended potential for Yb is `Yb_2`. In VASP .54, there are also `Yb` and `Yb_3` potentials. Yb, like the remaining lanthanoids, is most commonly in the 3+ oxidation state (although it can indeed sometimes exhibit the 2+ oxidation state). Using a `Yb_2` potential for an element that is commonly 3+ seems like it would be problematic. Additionally, the `Yb` potential is not oxidation state-specific.

What is the motivation for highlighting `Yb_2` as recommended given this information?

Re: Yb_2 as the "recommended" pseudopotential

Posted: Mon Jan 31, 2022 11:51 am
by alexey.tal
Hi,

If you know that Yb has 3+ oxidation state in your system you should use the Yb_3 potential. I have added Yb_3 in the recommended list to avoid any confusion.

Re: Yb_2 as the "recommended" pseudopotential

Posted: Wed Feb 02, 2022 11:51 pm
by andrew_rosen
Thanks for the reply. Oftentimes, I am running calculations in a high-throughput setting where the oxidation state is not known a priori. This is why I found it a little unusual that Yb_2 was recommended given no other information in the manual. But I agree, if it's known to be 3+, using Yb_2 would not be wise.

Thanks for adding Yb_3!