Solvent Polarity Effect on The Electronic Spectra of Laser Dye (P- Terphenyl Molecule )

Abstract

The aim of this  study is to investigate the effects of  solvents of various polarities on the electronic spectra(absorption and fluorescence) of p-terphenyl dye at room tempreture with concentrations 10^-4M , 10^-5M. The singlet state excited dipole moments  and ground state dipole moments were estimated from the equations of  Lippert  and  Bakshiev -Kawski and Chamma -Viallet using the variation of Stokes shift along with the solvent’s dielectric constant (Ɛ) and refractive  indices  (n). It was observed that excited  state dipole moments were found to be larger than the ground state ones. That indicates the redistribution of  electronic charge densities had been occured. Also, the experimental variations in the dipole moment values can be explains in terms of their possible resonance structures.