ONCV pseudopotentials

[ahsan_javed]

Hi, can ONCV pseudopotentials be used in VASP? I am working with SCAN functional and literature suggests oncv pps to be best for SCAN with QuantumEspresso. Need to know about VASP in this regard thanks

[martin.schlipf]

ONCV potentials are not compatible with VASP. More often than not the recommendation to use norm conserving potentials in other codes stems from the fact that PAW potentials are not implemented and/or tested for the feature. With VASP we will make features available with the PAW potentials due to their superior precision and energy cutoff. Hence we recommend to use PAW for all calculations.

[ahsan_javed]

This its okay to ignore this warning while using SCAN

-----------------------------------------------------------------------------
| |
| ----> ADVICE to this user running VASP <---- |
| |
| You enforced a specific xc type in the INCAR file but a different |
| type was found in the POTCAR file. |
| I HOPE YOU KNOW WHAT YOU ARE DOING! |
| |
-----------------------------------------------------------------------------

[martin.schlipf]

This warning is mostly to make you aware of the fact that you are changing the xc functional. Pseudopotential calculations have an arbitrary reference energy so only energy differences are meaningful. VASP chooses this reference energy for the free atom so that you do not need to recompute it. If you change the xc functional this reference needs to be recomputed. However this only matters if the energy of the atom is relevant like for the formation energy. Otherwise you should not see significant differences between a PAW optimized for a functional and a different one. You can try this for yourself and do a PBE calculation with the LDA PAW or vice versa.