Moment theory analysis of eROH- optical absorption spectra

Carmichael, Ian

doi:10.1021/j100447a002

Cited by 13 publications

(10 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Table we have listed values of 〈α(0)〉, 〈 r 2 〉, and 〈 T 〉 for solvated electrons in H 2 O and in D 2 O at different temperatures, , in THF, and in THF/H 2 O(D 2 O) mixtures. The quantities with the superscript exp are obtained directly from the experimental spectra in the restricted experimental spectral range, whereas the quantities marked by corr are obtained from the experimental spectra which were fitted and extended by a Gaussian and Lorentzian shape function beyond the experimentally observed spectral range (in order to approach the required integration limits 0 and ∞).…”

Section: Resultsmentioning

confidence: 99%

Optical Absorption of Solvated Electrons in Water and Tetrahydrofuran/Water Mixtures

1998

View full text Add to dashboard Cite

In the past Jou and Dorfman (J. Chem. Phys. 1973, 58, 4715) have determined the optical absorption spectra of solvated electrons (esolv -) in binary mixtures of tetrahydrofuran (THF) and water over the entire concentration range. From these experiments they concluded that the position of the absorption maximum and the width at half-height of the band are dominated by water. By additional experiments we show that at least for some mixtures with a mole fraction X(THF) ≤ 0.50, we obtain spectra at 298 K which agree almost completely with those of esolv - in pure water at elevated temperatures obtained by Jou and Freeman (J. Phys. Chem. 1979, 83, 2383). It follows that for this range of composition, excess electrons are obviously hydrated and the large amount of THF of up to X(THF) = 0.49 changes the water structure of the hydrated electron only slightly. The same effect can be produced by a temperature increase of T = 80 K in pure water. From the spectra we have determined equilibrium ground-state properties of the hydrated electron as a function of temperature and composition of the mixture. Results of quantum-statistical simulations on hydrated electrons show very poor agreement with the experimental results. Therefore, it seems to be presumptuous to take these simulations as a basis to explain the behavior of excess electrons in water on a femtosecond time scale.

show abstract

Section: Resultsmentioning

confidence: 99%

Optical Absorption of Solvated Electrons in Water and Tetrahydrofuran/Water Mixtures

1998

View full text Add to dashboard Cite

show abstract

“…The question about homogeneous vs inhomogeneous broadening in the optical absorption spectrum of the excess electron in water and other fluids, as well as the explanation of its asymmetry and extraordinary spectral width, has remained a standing problem for over three decades. Numerous attempts have been made to fit the experimental data by various line shapes − and superposition of lines. − In the computer simulations, by imposing an ordering of the p -states according to their energy, the resulting absorption contour was decomposed into a superposition of the contributions from separate s − p transitions. Each of the obtained three bands is claimed to be substantially inhomogeneously broadened by different structures of the solvent surroundings.…”

Section: Introductionmentioning

confidence: 99%

Early-Time Dynamics of the Photoexcited Hydrated Electron

et al. 1999

View full text Add to dashboard Cite

Employing photon echo techniques, we investigate the early relaxation dynamics of the equilibrated hydrated electron within the first 200 fs upon photoexcitation. The use of 5-fs laser pulses provided unprecedented temporal resolution of our measurements. We show that even for extremely short pulse durations the signals obtained in photon echo spectroscopy, can be described in the conventional way, provided care is taken of the spectral filtering effect and experimental beam arrangement. We next conclude that the absorption spectrum of the hydrated electrons is primarily homogeneously broadened. The comparison of two pulse photon echo experiments on pure water and on hydrated electrons allows us to measure the pure dephasing time of ∼1.6 fs. The line shape of the absorption spectrum is described excellently by an extended Lorentzian contour with a spectral width fully determined by the pure dephasing time. From the polarization-dependent transient grating experiments we establish that the polarization anisotropy of the hydrated electron falls to the zero value within 5 fs after initial excitation. A prominent role of a non-Condon effect due to strong coupling of the electron to neighboring water molecules is suggested. Based on the observed isotopic effect we concluded that the initial relaxation dynamics are determined by the inertial response of the water molecules which is librational in its origin. The microscopic picture of the early dynamics of the hydrated electron based on the experimental results is presented. Finally, we develop a theoretical model based on wave packet dynamics, which is capable of capturing the subtle features of the experimental data.

show abstract

“…The formulas ͑given in atomic units͒ are derived from dispersion relationships ͑Kramers-Kronig relations, f-sum rules͒ or by analogy to atomic systems using a one-electron representation. [11][12][13][14] Although the sum rules are rigorous, application of these formulas to solvated electrons depend upon two unproven assumptions. 15 First, the coupling of the electron to other electronic degrees of freedom must be sufficiently weak so that oscillator strength is not significantly transferred to or from the solvent spectrum.…”

mentioning

confidence: 99%