The determination of hyperpolarisabilities using density functional theory

Abstract

The theory for the calculation of the static polarisability α and hyperpolarisability β using density functional theory is presented. In particular the computational implementation of the coupled-perturbed Kohn—Sham equations is discussed. Calculations on CH 2O and CH 3CN are reported using large basis sets and accurate quadrature using the local density approximation (S-VWN). The results suggest that DFT is a promising method for the determination of these properties. Finally it is argued that the theory of Vignale, Rasolt and Geldart can be used as a basis for the determination of frequency-dependent polarisabilities.