DUGi

Basis set and electron correlation effects on initial convergence for vibrational nonlinear optical properties of conjugated organic molecules

http://dugi.udg.edu/item/http:@@@@hdl.handle.net@@2072@@372787

The level of ab initio theory which is necessary to compute reliable values for the static and dynamic (hyper)polarizabilities of three medium size π-conjugated organic nonlinear optical (NLO) molecules is investigated. With the employment of field-induced coordinates in combination with a finite field procedure, the calculations were made possible. It is stated that to obtain reasonable values for the various individual contributions to the (hyper)polarizability, it is necessary to include electron correlation. Based on the results, the convergence of the usual perturbation treatment for vibrational anharmonicity was examined

Support for this work under Grant Nos. BQU2002-04112-C02-02 and PB98-0457-C02-01 from the Dirección General de Enseñanza Superior e Investigación Científica y Técnica -MEC--Spain is acknowledged. One of us M.T. thanks the Generalitat of Catalunya for financial help through CIRIT Project No. FI/01-00699

American Institute of Physics