Static and dynamic polarisabilities, Cauchy coefficients and their anisotropies: an evaluation of DFT functionals

We have studied the behaviour of static and dynamic polarisabilities for a set of small molecules and compared it with earlier experimental and computational work. The polarisabilities have been calculated using non-local and hybrid functionals under density functional theory (DFT). Calculations at several low frequencies enable the Cauchy moment S(−4) to be found for both the isotropic and anisotropic polarisabilities. The DFT values obtained with the hybrid functional are in good agreement with experimental values. The PBE0 functional gives slightly more accurate results than the traditional CCSDLR method.