Static Dipole Polarizability and Hyperpolarizability of F2 from Density Functional Theory Calculations. Similarities and Dissimilarities with Conventional ab initio Results

We have calculated the bond-length dependence of the static dipole polarizability and hyperpolarizability of F2 relying on finite-field density functional calculations. At the internuclear separation of Re = 2.66816 a0 we obtain α/e2a02Eh−1 = 8.73 (B3LYP) and 8.60 (B3PW91), Δα/ e2a02Eh−1= 6.42 (B3LYP) and 6.32 (B3PW91), γ/ e4a04Eh−3 = 535 (B3LYP) and 503 (B3PW91) with a large, flexible [9s6p4d1f] basis set. For all three properties we observe that both B3LYPand B3PW91 yield values above the more accurate CCSD(T) results: CCSD(T) < B3PW91 < B3LYP. The discrepancy between DFT and conventional ab initio methods is more pronounced for the anisotropy of the (hyper)polarizability.