Ab initio and semi-empirical studies of the static polarizability and the second hyperpolarizability of diamond: finite Td symmetry models from CH4 to C281H172

The mean static polarizability and second hyperpolarizability of a series of diamond-like molecules capped by hydrogen atoms have been calculated. Both semi-empirical (MNDO, AM1, PM3) and ab initio Hartree–Fock (with basis sets STO-3G, 3-21G, 6-31G∗∗) methods have been used. The results enable the determination of the mean polarizability of diamond and an estimation of the second hyperpolarizability. The values are consistent with the little experimental data available.