COMPARATIVE STUDY OF THE MOLECULAR DYNAMICS OF ANTHRACENE AND ONE OF ITS DERIVATIVE (1-HYDROXYANTHRACENE) IN GAS PHASE AND ETHANOL

RHF AND DFT STUDY

Abstract

A comparative study of the molecular geometries of the organic semi-conductor material Anthracene and one of its derivative (1-hydroxyanthracene) in gas phase and ethanol is studied at the Restricted-HartreeFock (RHF) and Density Functional Theory (DFT) levels of theory by employing 6-31G basis set. The molecular structure, dipole moment, quadrupole moment, charge transfer, polarizability, energy and vibrational frequencies with Infrared (IR) and Raman intensities have been studied. Frequency analysis was carried out in all the cases to ensure that the optimized geometries correspond to total energy minima. At both level of theory it is predicted that the solvent (ethanol) has an effect of expanding the molecules as there is slight increase in most of the bond lengths, bond angles and dihedral angles as compare to gas phase analysis. For anthracene it is predicted that the bonds with the lowest bond lengths are R(1,17), R(6,20), R(13,22), R(14,23) with a bond length of 1.0719 Å in gas phase and ranging from 1.0751 to 1.0771 Armstrong in ethanol at the RHF level of theory while for 1 Hydroxyanthraceneit is predicted that the bond with the lowest bond length is R(7,15) with a bond
length of 1.0712 Å in gas phase and 1.0733 Å in ethanol at the RHF level of theory. The predicted dipole moment for Anthracene is almost zero at RHF/6-31G level and zero at B3LYP/6-31G level indicating that the molecule is not polar and the charge distribution is fairly symmetrical. The magnitude of the dipole moment obtained at B3LYP/6-31G level is slightly higher as compared to the corresponding values of the dipole moment at RHF/6-31G level. The quadrupole moment predicts that all two molecules are slightly elongated along the ZZ axis, with 1 Hydroxyanthracene showing the highest elongation at both levels of theory