Atomic spin densities from correlation-consistent basis sets

Recently introduced correlation-consistent (cc-) basis sets are used together with the quadratic configuration interaction (QCISD) correlation recovery technique and a hybrid density functional method, including both gradient corrections and a Hartree-Fock exchange contribution, to calculate the isotropic hyperfine coupling, a, in the electronic ground states of the atoms B-F. As expected, valence-only cc-basis sets are found to be inappropriate for spin density calculation with either of the above methods. Results from core-valence cc-basis sets converge satisfactorily toward experiment at QCISD, but the asymptotes of the density functional calculations match experiment only for nitrogen. At the complete basis set limit, the corresponding density functional values for the spin density at the nucleus is substantially overestimated for B and C but underestimated for O and F.