Journal of Physical Chemistry A, Vol.107, No.20, 4172-4183, 2003
Electronic and vibrational polarizabilities and hyperpolarizabilities of azoles: A comparative study of the structure-polarization relationship
Density functional theory (DFT) is used to study the static electronic dipole moments, polarizabilities, polarizability anisotropies, and first- and second-order hyperpolarizabilities of azoles. These properties are obtained with a finite field approach implemented in the DFT program ALLCHEM. The calculations were of all-electron type using a local exchange correlation functional. To investigate the dependence of polarizabilities and first- and second-order hyperpolarizabilities on the geometries, all structures were optimized with ALLCHEM and MSINDO. The influence of the substituted atoms on the properties is discussed. The vibrational contributions to the above properties of the considered compounds have also been computed using SCF theory and analytic property derivatives. Several methods (basis sets and approaches to determine the electron correlation contribution) have been employed to confirm the adequacy of the method, which was used. The electronic and vibrational properties are connected with various aspects of the electronic and vibrational structure and they are rationalized by simple concepts (resonance structures) and properties (fragments, derivatives). The present results are in satisfactory agreement with the available experimental data.