CONFINEMENT (block-type): subkey of atomtype
The global confinement option leads to discontinuous higher order derivatives in the basis function, leading to numerical instability. It is better to use smooth confinement. Smooth confinement means that the radial part of a function is multiplied with a Fermi-Dirac (FD) function. We have implemented smooth confinement at the atom type level. In a slab calculation this allows one to use different settings for surface atoms than for those in inner layers. You can specify the range and the decay speed of the FD function like
Confinement
Radius 7
Delta 0.7
SubEnd
If the decay 'Delta' is not specified it defaults to 0.1*'Radius'. Relativistic effects are treated correctly. If the confinement option is used in combination with the TAILS option, the calculation may run significantly faster. The confinement option can also be useful without the tails option in cases where near linear dependency reduces the numerical reliability of the results (cf. dependency keyword). This typically occurs for highly coordinated systems with large basis sets containing diffuse functions. For such cases, the confinement option (possibly in combination with the dependency keyword) reduces the numerical problems.
NB: does not work with the BasisDefaults key (because it is a sub key of AtomType).
