Calculation of vibrational frequencies, Energetic and some other Quantum Chemical Parameters for some Flavonoids

Abstract

Abstract Computational study objective understanding the molecular factors that influence their structural design electronic charge density on atoms and energetic properties, using quantum mechanics calculations of the Semiempirical theory PM3 and Density Functional Theory DFT of (B3LYP) with a 6-311++G (2d, 2p) by using Gaussian-09 program on Selected Phytomedicines molecules, Flavon, Claflanone, and Hesperetin. They were chosen because of their unique chemical structure, which enabled researchers to assess the impact of functional groups on physical properties. Theoretical study for physical Properties, bond length, energies, vibration modes, charge density and Mechanical Properties by Quantum Mechanical Calculations for Phytomedicines molecules. Both IR absorption intensities and vibration frequencies of 3N-6 for all species were measured and allocated, and correlations for the frequencies of related modes were observed using the Herzberg convention. In addition to certain physical properties such as heat of formation, total energy, electronic charge density on atoms, dipole moment, and energy gap (E= ELUMO-EHOMO), the calculated physical properties and quantum chemical parameters correlated for the three Phytomedicines molecules. The distribution of electronic charge density on the atoms of three molecules was also measured and analyzed using the Gaussian 09 program; all three molecules were studied and discussed at their equilibrium geometry, symmetry..