GerritJan Linker

Spin Density For openshell situations or for some closedshell UHF situations non zero spin densities exist and can be calculated. The definition of a closedshell situation has subtleties, but a simplistic definition of it might be that the probability of finding a spinup electron is identical to the probability of finding a spindown electron, everywhere in space. Thus, in contrast to the total electron density defined as the sum of alpha and beta densities above, it is convenient to define the spin density as the difference between the alpha spin density and the beta spin density. The spin density defines the excess probability of finding spinup over spindown electrons at a point in space and is zero everywhere for closedshell RHF situations.
