title: Determination of ground and excited state dipole moments of dipolar laser dyes by solvatochromic shift method.
abstract: The absorption and fluorescence spectra of three medium sized dipolar laser dyes: coumarin 478 (C478), coumarin 519 (C519) and coumarin 523 (C523) have been recorded and studied comprehensively in various solvents at room temperature. The absorption and fluorescence spectra of C478, C519 and C523 show a bathochromic and hypsochromic shifts with increasing solvent polarity indicate that the transitions involved are π→π(∗) and n→π(∗). Onsager radii determined from ab initio calculations were used in the determination of dipole moments. The ground and excited state dipole moments were evaluated by using solvatochromic correlations. It is observed that the dipole moment values of excited states (μe) are higher than corresponding ground state values (μg) for the solvents studied. The ground and excited state dipole moments of these probes computed from ab initio calculations and those determined experimentally are compared and the results are discussed.
authors.affiliation: Department of Physics, J.S.S. College, Dharwad 580 004, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Patil
authors.affiliation: Laser Spectroscopy Programme, Department of Physics, Karnatak University, Dharwad 580 003, India.
authors.forename: M N
authors.initials: MN
authors.lastname: Wari
authors.affiliation: Department of Physics, T.K.M. College of Arts and Science, Kollam 691 005, India.
authors.forename: C Yohannan
authors.initials: CY
authors.lastname: Panicker
authors.affiliation: Laser Spectroscopy Programme, Department of Physics, Karnatak University, Dharwad 580 003, India. Electronic address: him_lax3@yahoo.com.
authors.forename: S R
authors.initials: SR
authors.lastname: Inamdar
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D003374:Coumarins / Q000737:chemistry*; D007834:Lasers; D008958:Models, Molecular; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D004396:Coloring Agents; D003374:Coumarins; D012997:Solvents; C030123:coumarin
keywords: Coumarins; Dipolar laser dyes; Dipole moments; Solvatochromic and bathochromic shift; Stokes shift