Net Charge and Spin polarization

The net charge of the molecule and the net spin polarization can be controlled with the key charge.

CHARGE {NetQ {ab}}

NetQ

The net total charge of the molecule

ab

The net total spin polarization: the number of spin-α electrons in excess of spin-β electrons. Specification is only meaningful in a spin-unrestricted calculation. However, specification is not meaningfull in an unrestricted Spin-Orbit coupled calculation using the (non-)collinear approximation.

If the key is used, the first value in the argument is assigned to netQ, the net total charge, and the second to ab. If the key is not used at all, default values apply. The default for the net total charge is the sum of fragment charges: not necessarily neutral!! The fragment charges are the net total charges that were used in the fragment runs; this information is stored in the fragment files.

The default spin polarization is zero.

An unrestricted calculation with ab=0 (for instance by not specifying charge at all) is in fact a restricted run: it should give exactly the same as the restricted calculation, but it will use more CPU time.