Theoretical and experimental approach to the investigation of hyperpolarizability and charge transfer characteristics of NLO active 2′,3,4,4′,5-pentamethoxy chalcone with silver atoms adsorbed

Abstract

Organic crystals of 2′,3,4,4′,5-pentamethoxy chalcone (PMC), grown by slow evaporation technique, are subjected to spectroscopic and nonlinear optical analyses. The experimental and theoretical vibrational spectra confirm that the charge-transfer interaction between the methoxy group and phenyl ring through the ethylenic bridge of the PMC molecule must be responsible for the simultaneous IR and Raman activation of C=C stretching and ring modes. The Natural Bond Orbital (NBO) and Atoms In Molecules (AIM) calculations verify the presence of intramolecular hydrogen bonding in the molecule. The large NLO efficiency predicted for PMC is confirmed for the first time by powder SHG efficiency experiment by Kurtz and Perry, while the third order nonlinearity is measured by means of open-aperture Z-scan technique. From the results, the use of PMC for nonlinear optical applications is suggested. The Surface Enhanced Raman Scattering (SERS) spectral investigations have been performed to obtain the adsorption geometry of PMC on the silver surface. Density functional theory at B3LYP/SDD level has been used to compute energies of different configurations of silver adsorbed-PMC to find their stability, optimized geometry of the most stable configuration, and for characterizations including vibrational, NBO and hyperpolarizability analyses.