Hexadecapole moment, dipole and quadrupole polarizability of sulfur hexafluoride

We have obtained SCF and MP2 values for the polarizability and hyperpolarizability of sulfur hexafluoride. A large [8s6p5d2f/6s4p4d1f] basis set, consisting of 335 Gaussian-type functions, provides near-Hartree–Fock values for all properties of interest: −24.76 ea04 for the hexadecapole moment (Φ), 26.54 e2a02Eh−1 for the dipole polarizability (α), γzzzz=738, γxxzz=317 and γ̄=823 e4a04Eh−3 for the dipole hyperpolarizability, 227.5 e2a04Eh−1 for the mean quadrupole polarizability (C̄), 101.7 e2 a04 Eh−1 for the dipole–octopole polarizability (E) and Bzz,zz=−134, Bxz,xz=−156 e3 a04 Eh−2 for the dipole–dipole–quadrupole hyperpolarizability. At MP2 level the dipole polarizability varies with the S–F bond length (symmetric stretch) as [α(R)−α(R0)]/e2a20 Eh−1=25.38ΔR+13.72ΔR2−0.99ΔR3 where ΔR/a0=(RS−F−R0) and R0 is the experimental S–F separation. The value of Φ is lower than any experimental result, and E is lower than the best experimental estimate.