Yb_2 as the "recommended" pseudopotential

[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?

[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.

[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!