Affiliations: [a] Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Apartado 47102, Caracas 1020-A, Venezuela | [b] Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 21827, Caracas 1020-A, Venezuela | [c] Centro Nacional de Tecnología Química CNTQ, Complejo Tecnológico Simón Rodríguez CTSR, Base Aérea La Carlota, Caracas, Venezuela | [x] Centro Nacional de Tecnologia Quimica CNTQ, Complejo Tecnologico Simon Rodriguez CTSR, La Carlota, Caracas, Venezuela | [y] Departamento de Quimica, Facultad Experimental de Ciencias, La Universidad del Zulia LUZ, Maracaibo, Venezuela | [z] Centro de Quimica, Instituto Venezolano de Investigaciones Cientificas IVIC, Caracas, Venezuela
Abstract: We report a theoretical study of the electron correlation, basis sets and substituent effects on the average of the dipole polarizability and second hyperpolarizability, <α> and <γ>, respectively, of a pair of DAAD quadrupolar isomers. The geometric optimization calculations were carried out at the HF, MP2 and DFT (B3LYP and BHHLYP) levels of theory using different basis sets. The results show that the electron correlation effects for the dipole polarizability <alpha> are consistent between the MP2 and DFT levels, whereas for the second hyperpolarizability <γ> the DFT performance shown significant differences with respect to the corresponding MP2 results. This behavior does not change with the variation of the employed basis sets. Regarding to the substituent effects, the results show that electron donor groups in conjunction with extended basis sets increase the values of <alpha> and <γ> at all levels of theory. In particular, -N(CH3)2 and -OCH3 groups are the substituents that lead to the highest values for these properties. We have also found that there exists a geometry dependency associated to the type of isomer on the <gamma> values.
