Available pseudopotentials

Pseudopotentials stored in POTCAR files are available for all elements in the periodic table from the VASP Portal. These are mostly Projector augmented wave (PAW). All distributed pseudopotentials have been generated by G. Kresse. The PAW potentials have been created 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. We also list old US-PP potentials here, but those files are outdated, not supported and only distributed as is. Some VASP feature might yield undesired results with these files (e.g. metaGGA)

Lists of all pseudopotentials for calculations involving occupied states

We list all pseudopotentials available from the VASP Portal that are mostly optimized for the treatment of occupied states, and unoccupied states close to the Fermi level. We advise to use the latest set of potentials, potpaw.64 unless there is a specific reason to use another set.

potpaw.64 (latest)

Available PAW potentials generated with PBE intended for calculations involving mainly unoccupied states.

Available PAW potentials generated with LDA intended for calculations involving mainly unoccupied states.

potpaw.54

Available PAW potentials generated with PBE intended for calculations involving mainly unoccupied states.

Available PAW potentials generated with LDA intended for calculations involving mainly unoccupied states.

potpaw.52

Available PAW potentials generated with PBE intended for calculations involving mainly unoccupied states.

Available PAW potentials generated with LDA intended for calculations involving mainly unoccupied states.

potpaw.54 (original univie release version)

Available PAW potentials generated with PBE intended for calculations involving mainly unoccupied states.

Available PAW potentials generated with LDA intended for calculations involving mainly unoccupied states.

List of all pseudopotentials optimized for calculations involving unoccupied states

We list all pseudopotentials available from the VASP Portal that are optimized for the treatment of unoccupied states far above the Fermi level as well as occuoied states. Those are the pseudopotential with an _GW suffix. We advise to use the latest set of potentials, potpaw.64 unless there is a specific reason to use another set.

Recommendations and information regarding PAW potentials

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.

f-elements

Due to self-interaction errors, $f$ electrons are not handled well by the presently available density functionals. In particular, partially filled $f$ states are often incorrectly described. For instance, all $f$ states are pinned at the Fermi-level, leading to large overbinding for Pr-Eu and Tb-Yb. The errors are largest at quarter, and three-quarter filling, e.g., Gd is handled reasonably well since 7 electrons occupy the majority $f$ shell. These errors are DFT and not VASP related. Particularly problematic is the description of the transition from an itinerant (band-like) behavior observed at the beginning of each period to localized states towards the end of the period. For the $4f$ elements, this transition occurs already in La and Ce, whereas the transition sets in for Pu and Am for the $5f$ elements. A routine way to cope with the inabilities of present DFT functionals to describe the localized $4f$ electrons is to place the $4f$ electrons in the core. Such potentials are available and described below; however, they are expected to fail to describe magnetic properties arising $f$ orbitals. Furthermore, PAW potentials in which the $f$ states are treated as valence states are available, but these potentials are expected to fail to describe electronic properties when $f$ electrons are localized. In this case, one might treat electronic correlation effects more carefully, e.g., by employing hybrid functionals or introduce on-site Coulomb interaction.

For some elements, soft versions (_s) are available as well. The semi-core $p$ states are always treated as valence states, whereas the semi-core $s$ states are treated as valence states only in the standard potentials. For most applications (oxides, sulfides), the standard version should be used since the soft versions might result in $s$ ghost-states close to the Fermi-level (e.g., Ce_s in ceria). For calculations on intermetallic compounds, the soft versions are, however, expected to be sufficiently accurate.

Lanthanides with fixed valence

In addition, special GGA potentials are supplied for Ce-Lu, in which $f$ electrons are kept frozen in the core, which is an attempt to treat the localized nature of $f$ electrons. The number of f electrons in the core equals the total number of valence electrons minus the formal valency. For instance: According to the periodic table, Sm has a total of 8 valence electrons, i.e., 6 $f$ electrons and 2 $s$ electrons. In most compounds, Sm adopts a valency of 3; hence 5 $f$ electrons are placed in the core when the pseudopotential is generated. The corresponding potential can be found in the directory Sm_3. The formal valency n is indicted by _n, where n is either 3 or 2. Ce_3 is, for instance, a Ce potential for trivalent Ce (for tetravalent Ce, the standard potential should be used).