|LMAXTAU||=||6 if LASPH = .TRUE.|
By means of LMAXTAU one can set the maximum -quantum number included in the PAW one-center expansion of the kinetic energy density. The PAW one-center expansion of the density has component up to and including , where is the -quantum number of the partial waves on the POTCAR file, with the highest angular moment. If the PAW one-center expansion of the density has component up to , then the one-center expansion of the kinetic energy density has components up to .
This means that as a rule of thumb, for -elements: LMAXTAU=2, for : LMAXTAU=4, and for : LMAXTAU=6. If you are willing to live with the computational costs, the default for LMAXTAU should be safe in all cases, except those involving -elements.
N.B.: It is recommended to set LASPH=.TRUE., when using meta-GGA functionals, since these often result in aspherical charge densities (see Sec. 6.44).