STATIC DIPOLE POLARIZABILITIES OF ORGANIC-MOLECULES - AB-INITIO CALCULATIONS AND A PREDICTIVE MODEL

Large basis set ab initio electronic structure calculations have been carried out to find dipole polarizabilities of over 30 organic molecul es containing up to four non-hydrogen atoms. For these molecules, we s how that polarizabilities can be divided into transferable atomic cont ributions. From this demonstration of near-additivity of atomic contri butions to the molecular polarizability tenser, a simple predictive sc heme emerges. Tests of this scheme on molecules larger than in the ori ginal set show that individual tenser elements are predicted to within an average error of around 10% and isotropic polarizabilities have an average error of 3%. As predictions for experimental measurement, we report model values of dipole and quadrupole polarizabilities for cert ain series of molecules. The near-additivity of atomic contributions w e find also has important implications for modeling polarization arisi ng from intermolecular interaction.