Density functional calculations of molecular polarizabilities and hyperpolarizabilities

This paper presents dipole moments, static polarizabilities, first hyperpolarizabilities and second hyperpolarizabilities calculated in the framework of density functional theory. All calculations have been performed using a finite field approach implemented in our new density functional theory program ALLCHEM. The calculations were of all-electron type. Both local and gradient-corrected functionals have been used. The influence of first- and second-order field-induced polarization functions, the external field strength, the numerical integration technique and the exchange-correlation functionals on the calculation of polarizabilities and hyperpolarizabilities is discussed in detail. A systematic study including 23 small and medium size molecules demonstrates that the obtained polarizabilities as well as the first and second hyperpolarizabilities are in good qualitative agreement with experimental data. The described density functional method provides polarizabilities and hyperpolarizabilities considerably better than the Hartree-Fock method and almost as accurate as much more expensive correlation treatments. This work demonstrates that reliable predictions of electro-optical properties for molecules with 20 and more atoms are possible using an efficient implementation of density functional theory. (C) 1998 American Institute of Physics.