EXPERIMENTAL AND THEORETICAL STUDY OF ADSORPTION OF 1, 2 DIHYDROXY ANTHRAQUINONE ON SILVER NANOPARTICLES

Abstract

An experimental study on the adsorption of 1, 2 Dihydroxy anthraquinone (1,2DHAQ) on biosynthesized nanoparticles has been investigated. It is compared with
theoretically modeled surface complex using DFT calculation. Theoretical computations on the shifting of frontier molecular orbitals from HOMO to LUMO, Natural population analysis (NPA) and the orbital overlapping between silver cluster and 1,2DHAQ in NBO analysis have been associated with the redistribution of charges between silver and 1,2DHAQ. Reduction in the band gap of 1,2DHAQ after adsorption on silver combined with a redistribution of electron density in the molecular electrostatic potential (MEP) confirms the redistribution of charges resultant to the process of adsorption. In addition, an enhancement
in the calculated dipole moment and polarizability values are also obtained. Based on the Time-Dependent Density Functional Theory (TDDFT), UV-Visible spectra is derived which is in agreement with the experimental one. Theoretical and experimental FTIR spectrum is compared. Enhancement in the first order hyperpolarizability of 1,2DHAQ -Ag complex suggests its potential applications in the design of NLO devices.