title: Estimation of ground and excited state dipole moment of laser dyes C504T and C521T using solvatochromic shifts of absorption and fluorescence spectra.
abstract: The absorption and fluorescence spectra of laser dyes: coumarin 504T (C504T) and coumarin 521T (C521T) have been recorded at room temperature in a series of non-polar and polar solvents. The spectra of these dyes showed bathochromic shift with increasing in solvent polarity indicating the involvement of π→π⁎ transition. Kamlet-Taft and Catalan solvent parameters were used to analyze the effect of solvents on C504T and C521T molecules. The study reveals that both general solute-solvent interactions and specific interactions are operative in these two systems. The ground state dipole moment was estimated using Guggenheim's method and also by quantum mechanical calculations. The solvatochromic data were used to determine the excited state dipole moment (μ(e)). It is observed that dipole moment value of excited state (μ(e)) is higher than that of the ground state in both the laser dyes indicating that these dyes are more polar in nature in the excited state than in the ground state.
authors.affiliation: Department of Physics, Siddaganga Institute of Technology, Tumkur 572 103, India.
authors.forename: Jana
authors.initials: J
authors.lastname: Basavaraja
authors.affiliation: Department of Physics, Siddaganga Institute of Technology, Tumkur 572 103, India. Electronic address: sureshkumarhm@rediffmail.com.
authors.forename: H M
authors.initials: HM
authors.lastname: Suresh Kumar
authors.affiliation: Laser Spectroscopy Programme, Department of Physics, Karnatak University, Dharwad 580 003, India.
authors.forename: S R
authors.initials: SR
authors.lastname: Inamdar
authors.affiliation: Laser Spectroscopy Programme, Department of Physics, Karnatak University, Dharwad 580 003, India.
authors.forename: M N
authors.initials: MN
authors.lastname: Wari
mesh_terms: D003374:Coumarins / Q000737:chemistry*; D004583:Electrons; D005453:Fluorescence; D006860:Hydrogen Bonding; D054025:Lasers, Dye; D008958:Models, Molecular; D013050:Spectrometry, Fluorescence
chemical_list: D003374:Coumarins; C030123:coumarin
keywords: Bathochromic; Coumarin; Dipole moments; Laser dyes; Solvatochromic