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1st row elements

For Li (and Be), a standard potential and a potential which treats the $1s$ shell as valence states are available ( Li_sv, Be_sv). For many applications one should use the _sv potential since their transferability is much improved compared to the standard potentials.

For the other first row elements three pseudopotential versions exist. For most purposes the standard versions should be used. They work for cutoffs between 325 and 400 eV, where 370-400 eV are required to accurately predict vibrational properties, but binding geometries and energy differences are well reproduced with 325 eV. The typical bond length errors for first row dimers (N$_2$, CO, O$_2$) are about 1% (compared to more accurate DFT calculations not experiment). The hard pseudopotentials _h give results that are essentially identical to the best DFT calculations presently available (FLAPW, or Gaussian with huge basis sets). The soft potentials are optimised to work around 250-280 eV. They yield very reliable description for most oxides, such as V$_x$O$_y$, TiO$_2$, CeO$_2$, but fail to describe some structural details in zeolites (i.e. cell parameters, and volume).


next up previous contents
Next: Alkali and alkali-earth elements Up: The PAW potentials Previous: The PAW potentials   Contents
Georg Kresse
2007-03-01