IJSR - International Journal of Scientific Research

Rakesh Kumar Srivastav; Mihir Roychoudhury

Volume : VI, Issue : V, May - 2017

Electronic structure and intermolecular interaction energy calculations of a bipolar mesogen HO–(CH2)5–O–C6H4–C6H4–CN

Rakesh Kumar Srivastav, Mihir Roychoudhury

Abstract :

Molecular geometry of a biopolar mesogen HO–(CH2)5–O–C6H4–C6H4–CN (H5CBP) was fully optimized without any constraint and checked for imaginary frequencies using hyid density functional B3LYP combined with 6–31g** basis set taking crystallographic geometry as input. Using the optimized geometry, electronic structure of the H5CBP molecule has been evaluated on the basis of DFT calculation. Intermolecular interaction between a pair of H5CBP molecules have been analyzed in detail using optimized geometry and charge distributions obtained with the help of Gaussian03 program. Intermolecular interaction energy between a pair of H5CBP molecules have been evaluated by using Rayleigh– Schrodinger perturbation theory modified with multi–centered multi–pole expansion method for the electrostatic part and Kitaigorodskii formula for dispersion and repulsion terms (RS+K method). The results have been reported for separate stacking, in–plane and terminal interactions. The stacking interaction energy of H5CBP molecules was computed with different methods i.e. DFT, DFT–D and M06 methods. Analysis of the molecular geometry, molecular packing in crystal and mesogenic behavior has been carried out in the light of the obtained results.