Available pseudopotentials

Projector augmented wave (PAW) potentials are available for all elements in the periodic table from the VASP Portal. These are for the PAW method and are stored in POTCAR files. The distributed PAW potentials have been generated by G. Kresse following the recipes discussed in , whereas the PAW method has been first suggested and used by Peter Blöchl . Therefore, if you use any of the supplied PAW potentials, you should include these two references.

Except for the 1st-row elements, all PAW potentials are designed to work reliably and accurately at an energy cutoff of roughly 250 eV. This is a key aspect of making the calculation computationally cheap. The default energy cutoff is set by the ENMAX tag in the POTCAR file.

Why VASP recommends PAW potentials

Generally, the PAW potentials are more accurate than ultra-soft pseudopotentials (US-PP). There are two reasons for this: First, the radial cutoffs (core radii) are smaller than the radii used for US-PP. Second, the PAW potentials reconstruct the exact valence wavefunction with all nodes in the core region. Since the core radii of the PAW potentials are smaller, the required energy cutoffs and basis sets are also larger. If such high precision is not required, the older US-PP can be used in principle, but it is discouraged. This is because the energy cutoffs have not changed appreciably for C, N, and O. Thus, the increase in the basis-set size will usually be small so that calculations for compounds that include any of these elements are not more expensive with PAW than with US-PP.

Different versions

For most elements different versions of PAW potentials exist within a specific release (e.g. potpaw_PBE.54). The different POTCAR files can be destinguished by the following suffixes:

Suffix	Explanation	Example
_s	This suffix indicates a "softer" potential, with a higher core radius and a lower requirement for the plane-wave energy cutoff. Significant advantages in computation time is achieved at some cost of transferability and accuracy.	The O potential has a core radius of 1.52 atomic units (a.u.) and ENMAX of 400 electron Volts (eV). The O_s potential has a core radius of 1.85 a.u. and a cutoff of 282.9 eV.
_h	This suffix indicates a "harder" potential, with a smaller core radius and a higher requirement for the plane-wave energy cutoff. This type of potentials increases computational cost, but can be necessary, especially if short bonds are present.	The O_h potential has a core radius of 1.1 a.u. and a cutoff of 765.5 eV.
_pv	Semicore $p$ states are considered valence states. Additionally these type of potentials are a bit harder. Computational cost increases, but accuracy and transferability as well.	The Ti potential has four valence electrons, two in the $3d$ shell, and two in the $4s$ shell. Ti_pv adds six electrons in the $3p$ shell.
_sv	Semicore $p$ and $s$ states are considered valence states. Additionally these type of potentials are harder than those without a suffix. Computational cost increases, but accuracy and transferability as well.	Ti_sv adds two more electrons, so now we have a $3s^23p^63d^24s^2$ configuration with 12 total electrons
_d	Semicore $d$ states are considered valence states. Additionally these type of potentials are a bit harder. Computational cost increases, but accuracy and transferability as well.	The Ge potential has four valence electrons, two in the $4s$ shell, and two in the $4p$ shell. Ge_d adds ten electrons in the $3d$ shell.
_2 or _3	Pseudopotentials with an integer suffix denote a specific valence state. These potentials are only provided for the Lanthanides. Some $4f$ electrons for these potentials are put in the frozen core, although they are higher in energy than other valence states. Be careful when using these potentials and read the corrsponding section beforehand	The Er potential has 22 valence electrons with the configuration $4f^{12}5s^25p^66s^2$ and an energy cutoff of ~350 eV. Er_2 has 8 valence electrons with the configuration $5p^66s^2$ and a recommended cutoff energy of ~120 eV, while Er_3 has 9 valence electrons and the configuration $5p^65d^16s^2$ and a cutoff of ~155 eV.
_AE	These potentials are only provided for H, He, and Li. They are very hard and contain all electrons (AE). SOME MORE WORK NEEDED HERE, ESPECIALLY FOR THE DIFFERENCE BETWEEN Li_sv_GW and Li_AE_GW!	Both the He and the HE_AE pseudopotentials contain two electrons, but he _AE variant has an extremely small core radius of 0.6 a.u. (compared to 1.1 a.u. for He), and ENMAX of ~2135 eV.
_GW	These potentials are optimized for calculations by using different projectors and taking care to reproduce the all-electron scattering properties for energies far above the Fermi level. They are superior for excited state properties and any calculation considering like RPA, BSE, and MP2. There are some results that indicate that the GW potentials are also more accurate for standard DFT calculations, but the results should be very comparable with the standard potentials in most cases. Note that the _GW suffix is often combined with other suffixes.	The Ge and the Ge_GW potential do not differ in core-radius, recommended plane-wave-energy cutoff, or the reference configuration of the atom. However, the projectors are different.

List of all DFT-PAW potentials

Please consult the list of all available DFT-PAW potentials, except hydrogen-like potentials with fractional valence.

List of all GW/RPA-PAW potentials

Please consult the list of all available GW/RPA-PAW potentials that have been optimized for accurate scattering properties in the high-energy range.

Recommendations and information regarding PAW potentials

Hydrogen like potentials with fractional valence

Hydrogen-like potentials are supplied for a valency between 0.25 and 1.75, as listed in the table below. Further potentials might become available, and the list is not always up to date. Mind that the POTCAR files restrict the number of digits for the valency (typically 2, at most 3 digits). That is, using three H.33 potentials does not yield 0.99 electrons and not 1.00 electron. This can cause hole- or electron-like states that are undesirable. The solution is to slightly adjust the NELECT tag in the INCAR file.

Element (and appendix)	default cutoff ENMAX (eV)	valency
H.25	250	0.2500
H.33	250	0.3300
H.42	250	0.4200
H.5	250	0.5000
H.58	250	0.5800
H.66	250	0.6600
H.75	250	0.7500
H1.25	250	1.2500
H1.33	250	1.3300
H1.5	250	1.5000
H1.66	250	1.6600
H1.75	250	1.7500

First row elements

For the 1st row elements, three PAW versions exist. For most purposes, the standard version of PAW potentials is most appropriate. They yield reliable results for energy cutoffs between 325 and 400 eV, where 370-400 eV are required to predict vibrational properties accurately. Binding geometries and energy differences are already well reproduced at 325 eV. The typical bond-length errors for first row dimers (N₂, CO, O₂) are about 1% compared to more accurate DFT calculations. The hard pseudopotentials _h give results that are essentially identical to the best DFT calculations presently available (FLAPW, or Gaussian with very large basis sets). The soft potentials are optimized to work around 250-280 eV. They yield reliable description for most oxides, such as V_xO_y, TiO₂, CeO₂, but fail to describe some structural details in zeolites, i.e., cell parameters, and volume.

For Hartree-Fock (HF) and hybrid functional calculations, we strictly recommend using the standard, standard GW, or hard potentials. For instance, the O_s potential can cause unacceptably large errors even in transition metal oxides. Generally, the soft potentials are less transferable from one exchange-correlation functional to another and often fail when the exact exchange needs to be calculated.

Alkali and alkali-earth elements (simple metals)

For Li (and Be), a standard potential and a potential that treats the $1s$ shell as valence states are available (Li_sv, Be_sv). One should use the _sv potentials for many applications since their transferability is much higher than the standard potentials.

For the other alkali and alkali-earth elements, the semi-core $s$ and $p$ states should be treated as valence states as well. For lighter elements (Na-Ca) it is usually sufficient to treat the $2p$ and $3p$ states as valence states (_pv), respectively. For Rb-Sr the $4s$, $4p$, and $5s$, $5p$ states, respectively, must be treated as valence states (_sv). The standard potentials are listed below. The default energy cutoffs are specified as well but might vary from one release to the other.

p-elements

For Ga, Ge, In, Sn, Tl-At, the lower-lying $d$ states should be treated as valence states (_d potential). For these elements, alternative potentials that treat the $d$ states as core states are also available but should be used with great care.

d-elements

For the $d$ elements the same as for the as for the alkali and earth-alkali metals applies: the semi-core $p$ states and possibly the semi-core $s$ states should be treated as valence states. In most cases, however, reliable results can be obtained even if the semi-core states are kept frozen. As a rule of thumb the $p$ states should be treated as valence states, if their eigenenergy $\epsilon$ lies above 3 Ry.

When to switch from X_pv potentials to the X potentials depends on the required accuracy and the row for the $3d$ elements, even the Ti, V, and Cr potentials give reasonable results but should be used with uttermost care. $4d$ elements are most problematic, and I advice to use the X_pv potentials up to Tc_pv. For $5d$ elements the $5p$ states are rather strongly localized (below 3 Ry), since the $4f$ shell becomes filled. One can use the standard potentials starting from Hf, but we recommend performing test calculations. For some elements, X_sv potential are available (e.g. Nb_sv, Mo_sv, Hf_sv). These potentials usually have very similar energy cutoffs as the _pv potentials and can also be used. For HF-type and hybrid functional calculations, we strongly recommend using the _sv and _pv potentials whenever possible.