Spin-extended wave function for atomic sodium

The spin-extended Hartree-Fock (SEHF) function, obtained by projecting the appropriate spin component of a UHF determinant with subsequent optimization, is calculated for Na(S2) with four different basis sets. Energy reductions relative to RHF values are small. Spin density at the nucleus is 12% off experimental value and rather insensitive to changes in basis set. It is tentatively concluded that SEHF spin density values are much more reliable for atoms with open s shells than for those having open p shells.