The consistency analysis of different semiempirical calculations on second- And third-order nonlinear optical properties of donor-acceptor chromophores containing a-cyan

摘要

The static and frequency dependent average polarizability (<α>), first- and second-hyperpolarizabilities {<β > and <γ>) and HOMO and LUMO energies of donor-acceptor chromophores containing α-cyan (1a-c) have been investigated by using the AMI, MNDO, MNDO-d, PM3, RM1 and PM6 methods within a timedependent Hartree-Fock (TDHF) approaches. The electronic properties of 1a-c have been reported by employing two-state model calculated at ZINDO/S-SCl, PM3-SCI and RM1 -SCI methods. Also, the molecular hardness (η) and electronegativity (x) parameters have been obtained by using molecular frontier orbital energies. The <α>, <β>, <β> HOMO, LUMO energies, η and x parameters have been investigated with respect to the choice of different semiempirical methods. The variation graphics of β, β_o, η and X parameters according to the different semiempirical methods are presented. Furthermore, the variation graphics of β_0 with regard to the μ_(eg), βmu; and λ_(eg) are displayed. The frontier molecular orbital and electrostatic potential pictures of 1a-c using ZINDO/S-SCI level have been examined. The results of 1a-c display significant second- and third-order molecular nonlinearity.