Why are the total energy values different between my calculation and MP data?

pymatgen
1

I calculated for Sn (mp-117) using VASP 6.2.0 version.
However, my calculations(3.83eV/atom) and MP data (-4.01eV/atom) were different.
(MP is materialsproject)

I want to use Sn energy of my calculation as a reference element,
but I doubt whether it can be used due to the large difference (0.18 eV/atom) in energy value with MP data.

Please advice from seniors.

Thank you.

My calculation environment is as follows.

POSCAR = MP
INCAR = MP (Only ISMEAR changed from -5 to 1.)
KPOINTS = MP
POTCAR = Sn_d(POT_GGA_PAW_PBE_54)

2

I don’t think the 54 POTCARS are the ones used by Materials Project, they have a slightly older version and the energy differences can be large. I checked the 54 Sn_d compared to the one I have for materials project compatibility; while they both have the same TITEL line, which says 06Sep2000, the data is different. The 54 Sn_d has an EATOM of 1893.1092 eV, for example, compared to 1893.0782 for the one which Materials Project uses. This may be the cause of the problem.

4 Likes
3

I checked that the Sn_d of my POTCAR has an EATOM of 1893.1092eV.
And, i understand the POTCAR version used by the Materials project.

Steven, thanks for the very detailed explanation!

Have a nice day. :grinning: