Coupled perturbed Kohn-Sham calculation of static polarizabilities of periodic compounds

The Coupled Perturbed Hartree-Fock (CPHF) scheme recently implemented in the CRYSTAL06 code for systems periodic in 1-3 dimensions has been generalized to Density Functional Hamiltonians (CPKS, Coupled Perturbed Kohn-Sham). The dielectric tensor of Magnesium Oxide, Diamond, and Silicon is calculated with four different Hamiltonians, ranging from DFT, in the local density and gradient corrected approximations, to "hybrid" functional B3LYP and Hartree-Fock. The effect of the computational parameters (Pack-Monkhorst net and basis set) is explored. DIFT is shown to perform generally better than HF, as it is the case for other properties such as band gaps (which influence the CPHF and CPKS equations via the energy difference between occupied and virtual states) and vibration frequencies.