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The influence of temperature on C153 steady-state absorption and fluorescence kinetics in hydrogen bonding solvents.

Dobek K, Karolczak J - J Fluoresc (2012)

Bottom Line: It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed.Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime.We show that while such bonds do not affect the transition probability, they do change the S(0) an S(1) energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physics, Adam Mickiewicz University, Poznań, Poland. dobas@amu.edu.pl

ABSTRACT
In a recent paper (J Fluoresc (2011) 21:1547-1557) a temperature induced modulation of Coumarin 153 (C153) fluorescence lifetime and quantum yield for the probe dissolved in the polar, nonspecifically interacting 1-chloropropane was reported. This modulation was also observed in temperature dependencies of the radiative and nonradiative rates. Here, we show that the modulation is also observed in another 1-chloroalkane-1-chlorohexane, as well as in hydrogen bonding propionitrile, ethanol and trifluoroethanol. Change in the equilibrium distance between S (0) an S (1) potential energies surfaces was identified as the source of this modulation. This change is driven by temperature changes. It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed. Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime. Hydrogen bonds are formed by C153 also with hydrogen accepting solvents like propionitrile. We show that while such bonds do not affect the transition probability, they do change the S(0) an S(1) energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position. Finally, the influence of temperature on the energies of hydrogen bonds formed by C153 when acting as hydrogen donor or acceptor is reported.

No MeSH data available.


Related in: MedlinePlus

Oscillation with change in equilibrium distance of the Franck-Condon integral of two S0 and S1 harmonic oscillator wavefunctions corresponding to the same vibrational mode and two different members of its progression
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Fig11: Oscillation with change in equilibrium distance of the Franck-Condon integral of two S0 and S1 harmonic oscillator wavefunctions corresponding to the same vibrational mode and two different members of its progression

Mentions: Both steady-state absorption (Fig. 2) and fluorescence results (Fig. 10) indicate that a change in the equilibrium distance occurs on decreasing temperature. According to the Born-Oppenheimer approximation the transition dipole moment between the excited (ψ′′) and ground (ψ′) states is proportional to [24]:7\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {M_{e \to g}} = \left\langle {\psi \prime } \right/\widehat{\mu }\left/ {\psi \prime \prime } \right\rangle \propto {P_{el}}\left( {\overline R } \right) \cdot \int {\psi \prime {*_{vib}}\psi \prime {\prime_{vib}}dR}, $$\end{document}where is the purely electronic transition dipole moment, dependent on the R-centroid for the transition. The integral represents the overlap of the vibrational wavefunctions in both electronic states. Assuming the harmonicity of the oscillators representing molecular vibrations and no changes in the frequency of a selected oscillator between electronic states involved in the transition, one can quickly check that for a selected vibration mode (frequency) and two selected members of this mode progression in S0 and S1 states the integral in Eq. 7 can oscillate with changed in the way shown in Fig. 11.Fig. 11


The influence of temperature on C153 steady-state absorption and fluorescence kinetics in hydrogen bonding solvents.

Dobek K, Karolczak J - J Fluoresc (2012)

Oscillation with change in equilibrium distance of the Franck-Condon integral of two S0 and S1 harmonic oscillator wavefunctions corresponding to the same vibrational mode and two different members of its progression
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3473193&req=5

Fig11: Oscillation with change in equilibrium distance of the Franck-Condon integral of two S0 and S1 harmonic oscillator wavefunctions corresponding to the same vibrational mode and two different members of its progression
Mentions: Both steady-state absorption (Fig. 2) and fluorescence results (Fig. 10) indicate that a change in the equilibrium distance occurs on decreasing temperature. According to the Born-Oppenheimer approximation the transition dipole moment between the excited (ψ′′) and ground (ψ′) states is proportional to [24]:7\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {M_{e \to g}} = \left\langle {\psi \prime } \right/\widehat{\mu }\left/ {\psi \prime \prime } \right\rangle \propto {P_{el}}\left( {\overline R } \right) \cdot \int {\psi \prime {*_{vib}}\psi \prime {\prime_{vib}}dR}, $$\end{document}where is the purely electronic transition dipole moment, dependent on the R-centroid for the transition. The integral represents the overlap of the vibrational wavefunctions in both electronic states. Assuming the harmonicity of the oscillators representing molecular vibrations and no changes in the frequency of a selected oscillator between electronic states involved in the transition, one can quickly check that for a selected vibration mode (frequency) and two selected members of this mode progression in S0 and S1 states the integral in Eq. 7 can oscillate with changed in the way shown in Fig. 11.Fig. 11

Bottom Line: It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed.Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime.We show that while such bonds do not affect the transition probability, they do change the S(0) an S(1) energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physics, Adam Mickiewicz University, Poznań, Poland. dobas@amu.edu.pl

ABSTRACT
In a recent paper (J Fluoresc (2011) 21:1547-1557) a temperature induced modulation of Coumarin 153 (C153) fluorescence lifetime and quantum yield for the probe dissolved in the polar, nonspecifically interacting 1-chloropropane was reported. This modulation was also observed in temperature dependencies of the radiative and nonradiative rates. Here, we show that the modulation is also observed in another 1-chloroalkane-1-chlorohexane, as well as in hydrogen bonding propionitrile, ethanol and trifluoroethanol. Change in the equilibrium distance between S (0) an S (1) potential energies surfaces was identified as the source of this modulation. This change is driven by temperature changes. It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed. Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime. Hydrogen bonds are formed by C153 also with hydrogen accepting solvents like propionitrile. We show that while such bonds do not affect the transition probability, they do change the S(0) an S(1) energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position. Finally, the influence of temperature on the energies of hydrogen bonds formed by C153 when acting as hydrogen donor or acceptor is reported.

No MeSH data available.


Related in: MedlinePlus