# Measurement of Dipole Moments and Lifetimes of Triplet States of Fluorenone and Its Derivatives by Time Resolved Microwave Dielectric Absorption.

15 Apr 1998-Journal of the Physical Society of Japan (THE PHYSICAL SOCIETY OF JAPAN)-Vol. 67, Iss: 4, pp 1220-1225

TL;DR: In this paper, the authors used microwave dielectric absorption to study the excited triplet states formed by the laser flash photolysis and reported the triplet state lifetime and dipole moments of fluorenone and its derivatives.

Abstract: The technique of time resolved microwave dielectric absorption has been used to study the excited triplet states formed by the laser flash photolysis. The details of the experimental method and apparatus are discussed. The triplet state lifetimes and triplet state dipole moments of fluorenone and its derivatives are reported. The triplet state lifetime of fluorenone agrees with that obtained by optical absorption. The lifetime measurements with argon purging and with air equilibrated solution confirm the formation of triplet states. A marked increase in the triplet state dipole moment of fluorenone and its derivatives is observed and implies that their lowest triplet state is of (π, π * ) in nature.

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05 May 2012TL;DR: In this article, a 2D finite difference time domain (FDTD) was used to evaluate the forward problem and the inverse problem was solved via a Bayesian approach via a posterior distribution over the model parameters such as complex permittivity.

Abstract: : The motivation of this work is to quantify the degradation of aging electrical cables. The dielectric material parameter of insulation can be correlated with degradation. In this paper, the forward problem is posed as a microwave nondestructive evaluation (NDE) problem. A 2D finite difference time domain (FDTD) was used to evaluate the forward problem. The inverse problem is solved via a Bayesian approach. The Bayesian formulation describes the solution as a posterior distribution over the model parameters such as complex permittivity. Since there is no analytical solution for the posterior distribution, the Markov Chain Monte Carlo (MCMC) method is employed to numerically solve for it. The Metropolis-Hasting algorithm is used in particular. Results for computational experiments are demonstrated to show feasibility of this approach.

1 citations

### Cites background from "Measurement of Dipole Moments and L..."

...Time-Resolved Microwave Dielectric Absorption (TRMDA) enables the measurement of the evanescent electrical field leaking from the probe into the cable insulation by using cavity resonator [2]....

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17 Oct 2011

TL;DR: In this paper, a stochastic inversion technique based on the Metropolis-Hasting algorithm was applied to the problem of quantitative nondestructive evaluation (QNDE) of material aging parameters.

Abstract: : The quantitative nondestructive evaluation (QNDE) of material aging parameters continues to be a very challenging problem. In our approach, we formulated a forward problem arising in specific micro guided wave test. A stochastic inversion technique based on the Metropolis-Hasting algorithm was applied to the problem. The feasibility and validity of the approach was demonstrated through computational experiments.

### Cites background from "Measurement of Dipole Moments and L..."

...Time-Resolved Microwave Dielectric Absorption (TRMDA) enables to measure evanescent electrical field leaking from the probe into the cable insulation by using cavity resonator [2]....

[...]

##### References

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TL;DR: The dipole moments of the oxides from benzophenone and dibenzosurberone are 4.0 and 3.8 D, respectively as discussed by the authors, which is the best known dipole moment for carbenes.

Abstract: Carbonyl oxides, generated by reaction of carbenes with oxygen, have been studied in time-resolved dielectric loss experiments. The dipole moments of the oxides from benzophenone and dibenzosurberone are 4.0 and 3.8 D, respectively.

20 citations

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15 Feb 1977TL;DR: In this paper, the difference in dipole moment of the zero-field (zf) levels of the lowest triplet state has been determined for a number of aromatic carbonyl molecules from the observed first order Stark effect on the optically detected electron spin transitions.

Abstract: The difference in the dipole moment of the zero-field (zf) levels of the lowest triplet state has been determined for a number of aromatic carbonyl molecules from the observed first order Stark effect on the optically detected electron spin transitions. The magnitude of the difference has been found to have a correlation with the energy gap between 3nπ* and 3ππ* states, suggesting that the observed difference in the dipole moment results from anisotropic spin—orbit (s.o.) coupling in the triplet manifold. Qualitative agreement between the results and the simple theory of s.o. coupling is obtained. A new method is proposed to determine the dipole moment, μ2, of the higher triplet state which is coupled to T1 via s.o. coupling from the microwave spectra obtained by using the different phosphorescence Stark components for detection. The values of μ2 for duraldehyde, p-chlorobenzaldehyde and benzaldehyde are determined in this manner.

18 citations

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TL;DR: In this paper, the absorption spectra and steady state fluorescence spectra of fluorenone have been obtained at room temperature for various concentrations in a series of non polar and polar solvents.

Abstract: The absorption spectra and steady state fluorescence spectra of fluorenone have been obtained at room temperature for various concentrations in a series of non polar and polar solvents. The concentration effect shows two fluorescence bands, one at shorter wavelength due to monomer and another at longer wavelength due to excimer formation by triplet-triplet annihilation process. The excited state dipole moments of both monomer and dimer are calculated by the method of solvatochromism. A reasonable agreement has been observed between the values obtained by the method of solvatochromism and electrochromism.

12 citations