Computational modeling and ultraviolet absorptions calculation of 5,6,7-trihydroxy-4'-methoxyflavone using DFT & TD-DFT methods

This work is a continuation of a previous investigation about the electronic structure of a flavonoid extracted from marine algae. This paper presents the results of molecular modeling and ultraviolet transitions by employing density functional DFT and TD-DFT methods. Geometry of the molecule were optimized using B3LYP functional at 6-311G (d,p) level of theory and electronic transitions were simulated using TD-DFT methods in gas phase. The major electronic transition appearing at 353.51nm corresponds to 75% contribution in HOMO to LUMO transition and can be attributed to. π-π* transition. There were 78 filled molecular orbitals were calculated by TD-DFT method and the energy gap between HOMO and LUMO orbitals were found to be 4.02 eV