Polarizabilities of Sc and Ti atoms and dispersion coefficients for their interaction with helium atoms

The dynamic scalar and tensor polarizabilities of Sc and Ti are computed with time-dependent density functional theory. These polarizabilities are used to compute the isotropic and anisotropic dispersion interactions in ScHe and TiHe. We find C-6,C-0(ScHe)=30.00, C-6,C-2(ScHe)=-1.63, C-6,C-0(TiHe)=28.40, and C-6,C-2(TiHe)=-0.90 (E(h)a(0)(6)). We show that an estimate of the dispersion anisotropy based on static polarizabilities results in an overestimation by a factor of 2.