Sana Zafar, Zahid H Khan and Mohd Shahid Khan
Keywords: DFT, non linear optics, polarizability, first hyperpolarizability, frontier molecular orbital’s, Ab initio.
Abstract: The Donor-Acceptor type conjugated molecular structures containing pyridine as a bridge have been explored for Non linear optical properties. The ab- initio Hartee Fock calculations and Density Functional Theory with B3LYP method have been carried out employing 6-31G basis set. The dipole moments (?), polarizability (?), first hyperpolarizability (?), and HOMO-LUMO energy gap are calculated using the same level of theory. The dependence of the hyperpolarizability of different molecular structure on the nature of donor and acceptor on the pyridine is discussed on the basis of molecular orbital picture. Of all the molecular systems studied, the molecular system containing nitro as an acceptor and dimethylaniline as a donor is found to have largest value of hyperpolarizability; 49.92 X 10-30 esu and 164.61x10-30 esu with ab-initio/HF and DFT/B3LYP respectively. The large value of ? for the Donor-Acceptor pyridine derivative suggests the potential applications of these molecular systems in the development of non linear materials.
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