A study on physical properties of Coronene oxide as a function of number of oxygen atoms and temperature by density functional theory

Abstract

The electronic properties like (HOMO, LUMO levels and Energy gap), and spectroscopic properties (IR spectra) in addition to thermodynamics characteristics like (Gibbs free Energy, Enthalpy, Entropy, and Heat capacity) of Coronene C24 and reduced Coronene oxide C24Ox where x=1-5 is a number of oxygen atoms and different temperature from (298 – 398) K were studied. The methodology utilized in this study involved the application of Density Functional Theory (DFT) using the Hybrid functional B3LYP (Becke, 3-parameters, Lee –Yang-Parr) with 6-311G** basis sets. The band gap of Coronene (C24) 3.5 eV was calculated, while for reduced coronene oxide C24O - C24O5 has been varied from (1.68 to 0.89) eV due to broken symmetry and adding levels inside the energy gap. The IR intensity of C24O5 increases with increasing temperature between (298 and 398) K because of the number of excited atoms, the spectroscopic properties were compared with experimental results, in particular the Longitudinal Optical (LO) mode of vibration for graphene oxide 1582 cm-1 which agreed well. The Gibbs free energy and enthalpy decreased (in the negative sign) with an increased number of oxygen atoms and temperatures which means an exergonic reaction.