Solvent effects on the dipole moments and photo physical properties of laser dye

The absorption and emission spectra of fluorescent laser dye namely, 4,4”’-bis-2-butyyloctyl-oxy)-P-quaterphenyl have been recorded at room temperature in solvents of different polarities. The exited state dipole moments (µe) have been estimated from Lippert’s, Bakhshiev’s and Kawski-Chamma-Viallet’s equations using the variation of Stoke’s shift with the solvent dielectric constant and refractive index. The geometry of the molecule has been fully optimized and the µg has also been calculated theoretically by Gaussian 03 software using B3LYP/6-31g* level of theory. The µg and µe have been calculated by means of solvatochromic shift method. It has been observed that µe is higher than µg, indicating a substantial redistribution of the π-electron densities in a more polar excited state for the selected laser dye. Further, the changes in the dipole moment (µ) has been calculated both from solvatochromic shift method and microscopic empirical solvent polarity parameter (E) and values are compared.

Examining the spectroscopic features and quantum chemical computations of a Quinoline derivative: Experimental and theoretical insights into the photophysical characteristics

503-515The solvatochromic studies in a Quinoline derivative molecule namely Quinolin-8-ol (QO) have been carried out at ambient temperature using absorption and fluorescence spectroscopy. The QO molecule shows the bathochromic shift with increase in solvent polarity demonstrating π → π* transition. The solvatochromic data coupled with quantum mechanical calculations has been used to estimate change in dipole moment of the molecule after excitation. It has been found that excited state dipole moment is greater than the corresponding ground state dipole moment. Further, it is observed that excited and ground state dipole moments are parallel. The chemical reactivity and kinetic stability of QO molecule are investigated using Frontier molecular orbital (FMO) analysis. Natural bond orbital (NBO) analysis shows proton transfer within the selected donor-acceptor depicting large energy of stabilization for QO molecule. The calculated Fukui functions infer the local softness and local eletrophilicity index of QO molecule. The theoretically simulated UV-Vis absorption spectrum of QO molecule matches well with the experimental spectrum

Examining the spectroscopic features and quantum chemical computations of a Quinoline derivative: Experimental and theoretical insights into the photophysical characteristics

The solvatochromic studies in a Quinoline derivative molecule namely Quinolin-8-ol (QO) have been carried out at ambient temperature using absorption and fluorescence spectroscopy. The QO molecule shows the bathochromic shift with increase in solvent polarity demonstrating π → π* transition. The solvatochromic data coupled with quantum mechanical calculations has been used to estimate change in dipole moment of the molecule after excitation. It has been found that excited state dipole moment is greater than the corresponding ground state dipole moment. Further, it is observed that excited and ground state dipole moments are parallel. The chemical reactivity and kinetic stability of QO molecule are investigated using Frontier molecular orbital (FMO) analysis. Natural bond orbital (NBO) analysis shows proton transfer within the selected donor-acceptor depicting large energy of stabilization for QO molecule. The calculated Fukui functions infer the local softness and local eletrophilicity index of QO molecule. The theoretically simulated UV-Vis absorption spectrum of QO molecule matches well with the experimental spectrum

Solvent effects on the dipole moments and photo physical properties of laser dye

749-754The absorption and emission spectra of fluorescent laser dye namely, 4,4”’-bis-2-butyyloctyl-oxy)-P-quaterphenyl have been recorded at room temperature in solvents of different polarities. The exited state dipole moments (µe) have been estimated from Lippert’s, Bakhshiev’s and Kawski-Chamma-Viallet’s equations using the variation of Stoke’s shift with the solvent dielectric constant and refractive index. The geometry of the molecule has been fully optimized and the µg has also been calculated theoretically by Gaussian 03 software using B3LYP/6-31g* level of theory. The µg and µe have been calculated by means of solvatochromic shift method. It has been observed that µe is higher than µg, indicating a substantial redistribution of the π-electron densities in a more polar excited state for the selected laser dye. Further, the changes in the dipole moment (µ) has been calculated both from solvatochromic shift method and microscopic empirical solvent polarity parameter (E) and values are compared.

Quantum chemical computations and photophysical spectral features studies of two coumarin compounds

An attempt was made to determine the ground state and excited state dipole moments and quantum chemical computations of two coumarin compounds, namely 3-hydroxy-3-[2-oxo-2-(2-oxo-2H-chromen-3-yl)-ethyl]-1,3-dihydro-indol-2-one (3HOCE) and 3-[2-(8-methoxy-2-oxo-2H-chromen-3-yl)-2-oxo-ethylidene]-1,3-dihydro-indol-2-one (3MOCE). Both compounds displayed a red shift with enhancement in solvent polarity. The larger excited state dipole moment indicated the more polar nature of the selected compounds in the excited state than in the ground state. Kinetic stability and chemical reactivity of the selected compounds were studied with help of the quantum chemical properties of the compounds such as frontier molecular orbital analysis using density functional theory calculations with B3LYP/6?311+G (d, p) basis sets. Molecular electrostatic potential, Mulliken charges, natural bond orbital, and nonlinear optical properties were further studied. NBO analysis showed proton transfer within the selected donor?acceptor, depicting the large energy of stabilization for the compounds. The calculated Fukui function inferred the local softness and electrophilicity indices of used solute compounds.Scopu