PLS prediction of hyperpolarizabilities for donor-bridge-acceptor organic systems

Abstract

Elevated magnitudes of the first and second static hyperpolarizabilities (AM1/TDHF), respectively, of organic molecules having electron-donation (D) and electron-accepting (A) groups can be obtained through of selection of molecular systems with appropriate structural and electronic parameters. The Homo-Lumo energy gap, the total number of π-electrons of the molecule, the Homo energy, and the ground state dipole moment were the parameters considered in this work. The designed D-A organic molecules investigated have polyenic/mesoionic bridge, which afford large β and γ hyperpolarizabilities, associated for different strength of donor-acceptor pairs. Large data sets of these parameters for the molecules, obtained from quantum chemistry semiempirical calculations with AM1 hamiltonian, were submitted to a principal components analysis (PCA). In addition, a model was proposed based in a principal components regression (PCR), having in mind the prevision and selection of organic molecules with potential applications in nonlinear optics.