The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
H D Patil - One of the best experts on this subject based on the ideXlab platform.
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Estimation of Ground and Excited State Dipole Moments of Some Laser Dyes
2020Co-Authors: Kalpana M Painagoni, H D PatilAbstract:The ground state (μg) and the excited state (μe) Dipole Moments of three laser dyes namely 5-chloro-2phenylindole (CPI), 5-methyl-2-phenylindole (MPI) and 1, 3-diphenyl benzene (MT) were studied at room temperature in various solvents. The ground state Dipole Moments (μg) of all the three laser dyes were determined experimentally by Guggenheim method. The excited state Dipole Moments (μe) were estimated from Lippert’s, Bakshiev’s and Chamma Viallet’s equations by using the variation of the Stokes shift with the solvent dielectric constant and refractive index. Ground and excited state Dipole Moments were evaluated by means of solvatochromic shift method and also the excited state Dipole Moments are determined in combination with ground state Dipole Moments. It was observed that Dipole moment values of excited states (μe) were higher than corresponding ground state values (μg), indicating a substantial redistribution of the π-electron densities in a more polar excited state for all the dyes investigated.
A. N. Sobchuk - One of the best experts on this subject based on the ideXlab platform.
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Dipole Moments of 4'-aminoflavonol fluorescent probes in different solvents.
Journal of Fluorescence, 2020Co-Authors: N. A. Nemkovich, Wolfram Baumann, V. G. Pivovarenko, A. N. Rubinov, A. N. SobchukAbstract:Electrooptical absorption measurements (EOAM) were used to measure the Dipole Moments of the normal form of 4′-(dimethylamino)-3-hydroxyflavone (FME), and 4′ N-(15-azacrown-5)-3-hydroxyflavone (FCR) in 1,4-dioxane, toluene, and cyclohexane. With these probes excited-state intramolecular proton transfer (ESIPT) takes place. For comparison, the Dipole Moments of 4′-(dimethylamino)-3-metoxyflavone (FME3ME), for which ESIPT is lacking, were measured, too. For all three probes the ground (μg) and excited Franck-Condon state (μeFC) electrical Dipole Moments are parallel to each other and also parallel to the transition Dipole moment. The electrical Dipole Moments of FCR, FME, and FME3ME in their ground state have values within the range (12.0–17.7) × 10−30 C m. Upon optical excitation, the Dipole Moments increase by (41.9–52.9) ×10−30 C m. The value of the change of the Dipole moment vector Δaμ with excitation to the Franck-Condon state and the value of the vector μeFC for FCR and FME are practically independent on the solvent polarity. From this point of view and due to large values of the Dipole Moments FCR and FME are very promising probes for the investigation of the distribution of the local polarity in biological systems using site-selective excitation of the different sites. Our steady-state fluorescence studies on FME and FCR have demonstrated a high spectral sensitivity of the normal form to such solvent characteristics as polarity.
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Dipole Moments of 4′-Aminoflavonol Fluorescent Probes in Different Solvents
Journal of Fluorescence, 2005Co-Authors: N. A. Nemkovich, V. G. Pivovarenko, W. Baumann, A. N. Rubinov, A. N. SobchukAbstract:Electrooptical absorption measurements (EOAM) were used to measure the Dipole Moments of the normal form of 4′-(dimethylamino)-3-hydroxyflavone (FME), and 4′ N -(15-azacrown-5)-3-hydroxyflavone (FCR) in 1,4-dioxane, toluene, and cyclohexane. With these probes excited-state intramolecular proton transfer (ESIPT) takes place. For comparison, the Dipole Moments of 4′-(dimethylamino)-3-metoxyflavone (FME3ME), for which ESIPT is lacking, were measured, too. For all three probes the ground (μ_g) and excited Franck-Condon state (μ_e^FC) electrical Dipole Moments are parallel to each other and also parallel to the transition Dipole moment. The electrical Dipole Moments of FCR, FME, and FME3ME in their ground state have values within the range (12.0–17.7) × 10^−30 C m. Upon optical excitation, the Dipole Moments increase by (41.9–52.9) ×10^−30 C m. The value of the change of the Dipole moment vector Δ^aμ with excitation to the Franck-Condon state and the value of the vector μ_e^FC for FCR and FME are practically independent on the solvent polarity. From this point of view and due to large values of the Dipole Moments FCR and FME are very promising probes for the investigation of the distribution of the local polarity in biological systems using site-selective excitation of the different sites. Our steady-state fluorescence studies on FME and FCR have demonstrated a high spectral sensitivity of the normal form to such solvent characteristics as polarity.
Yavuz Onganer - One of the best experts on this subject based on the ideXlab platform.
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Solvent effect on the ground and excited state Dipole Moments of fluorescein
Journal of Molecular Structure-theochem, 2001Co-Authors: Bilal Acemioğlu, Mustafa Arık, Hasan Efeoglu, Yavuz OnganerAbstract:Abstract The ground-state and excited-state Dipole Moments of fluorescein were studied at room temperature in n -alcohols (methanol– n -hexanol) and acetonitrile and acetonitrile–benzene solvent mixtures. The excited-state Dipole Moments were estimated from Lippert's, Bakhshiev's and Chamma–Viallet's equations by using the variation of the Stokes' shift with the solvent dielectric constant and refractive index. Experimental ground-state Dipole Moments for fluorescein in n -alcohols, acetonitrile and acetonitrile–benzene solvent mixtures were estimated by the Guggenheim–Smith method (GSM). It was determined that Dipole Moments of the excited-state were higher than those of the ground-state in n -alcohols while they were lower than those of the ground-state in acetonitrile and acetonitrile–benzene solvent mixtures. The solute–solvent interactions on the ground-state and the excited-state Dipole Moments of fluorescein are discussed.
William J. Marciano - One of the best experts on this subject based on the ideXlab platform.
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Lepton Dipole Moments - Lepton Dipole Moments
arXiv: High Energy Physics - Experiment, 2009Co-Authors: B. Lee Roberts, William J. MarcianoAbstract:From the famous experiments of Stern and Gerlach to the present, measurements of magnetic Dipole Moments, and searches for electric Dipole Moments of “elementary” particles have played a major role in our understanding of sub‐atomic physics. In this talk I discuss the progress on measurements and theory of the magnetic Dipole Moments of the electron and muon. I also discuss a new proposal to search for a permanent electric Dipole moment (EDM) of the muon and put it into the more general context of other EDM searches.
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lepton Dipole Moments
arXiv: High Energy Physics - Experiment, 2009Co-Authors: Lee B Roberts, William J. MarcianoAbstract:From the famous experiments of Stern and Gerlach to the present, measurements of magnetic Dipole Moments, and searches for electric Dipole Moments of “elementary” particles have played a major role in our understanding of sub‐atomic physics. In this talk I discuss the progress on measurements and theory of the magnetic Dipole Moments of the electron and muon. I also discuss a new proposal to search for a permanent electric Dipole moment (EDM) of the muon and put it into the more general context of other EDM searches.
Rollin A. King - One of the best experts on this subject based on the ideXlab platform.
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On the accuracy of computed excited-state Dipole Moments.
Journal of Physical Chemistry A, 2008Co-Authors: Rollin A. KingAbstract:: The Dipole Moments of furan and pyrrole in many electronically excited singlet states have been determined using coupled cluster theory including large one-electron basis sets. The inclusion of connected triple excitations is shown to uniformly decrease the equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) excitation energies by 0.04-0.24 eV, with an average reduction of 0.08 eV. Using a basis set larger than DZP (++)D (double-zeta plus polarization augmented with atom- and molecule-centered diffuse functions) uniformly increases the computed EOM-CCSD excitation energies by 0.03-0.29 eV, with an average increase of 0.20 eV. The corresponding shifts in excited-state Dipole Moments are more erratic. Including connected triple excitations changes the computed Dipole Moments by an rms amount of 0.17 au. More importantly, using a larger basis set shifts the Dipole Moments by an rms amount of 0.52 au, with an increase or a decrease being equally likely. The CC Dipole Moments are compared to those from time-dependent density functional theory (TD-DFT) computed by Burcl, Amos, and Handy [ Chem. Phys. Lett. 2002, 355, 8]. For 29 excited states of furan and pyrrole, the predicted TD-DFT Dipole Moments differ from the CC results by rms amounts of 1.6 au (HCTH functional) and 1.5 au (B97-1 functional). Including the asymptotic correction to TD-DFT developed by Tozer and Handy [ J. Chem. Phys. 1998, 109, 10180; J. Comput. Chem. 1999, 20, 106] reduces the rms differences for both functionals to 1.2 au. If those Rydberg excited states with very large polarizabilities are excluded, the rms differences from the CC results for the remaining 17 excited states become 1.31 au (HCTH) and 0.88 au (B97-1). For asymptotically corrected functionals and this subset of states, the rms differences from the CC results are only 0.54 au (HCTHc) and 0.34 au (B97-1c). Thus, the Tozer-Handy asymptotic correction for TD-DFT significantly improves the predictions of excited-state Dipole Moments. For excited states without very large polarizabilities, good agreement is achieved between excited-state Dipole Moments computed by coupled cluster theory and by the asymptotically corrected B97-1c density functional.
