Temperature and isotope effects on the shape of the optical absorption spectrum of solvated electrons in water

Jou, Fang‐Yuan; Freeman, Gordon R.

doi:10.1021/j100481a016

Cited by 244 publications

(313 citation statements)

References 9 publications

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“…Transient absorption (TA) spectra 23 and is similar to that observed by nanosecond flash photolysis of α-tocopherol in micellar solutions. 13,15 As the hydrated electron absorption increases from 1 to 25 ps, there is evidence of a parallel growth in absorbance at 460-470 nm which corresponds to the absorption maximum of the tocopheroxyl radical cation, as observed for MDL74030 in acidic aqueous solution 12 and α-tocopherol in MeCN and some other solvents.…”

Section: Resultssupporting

confidence: 61%

Ultrafast Vibrational Spectroscopic Studies on the Photoionization of the α-Tocopherol Analogue Trolox C

et al. 2014

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The initial events after photoexcitation and photoionization of α-tocopherol (vitamin E) and the analogue Trolox C have been studied by femtosecond stimulated Raman spectroscopy, transient absorption spectroscopy and time-resolved infrared spectroscopy. Using these techniques it was possible to follow the formation and decay of the excited state, neutral and radical cation radicals and the hydrated electron that are produced under the various conditions examined.α-Tocopherol and Trolox C in methanol solution appear to undergo efficient homolytic dissociation of the phenolic -OH bond to directly produce the tocopheroxyl radical. In contrast, Trolox C photochemistry in neutral aqueous solutions involves intermediate formation of a radical cation and the hydrated electron which undergo geminate recombination within 100 ps in competition with deprotonation of the radical cation. The results are discussed in relation to recently proposed mechanisms for the reaction of α-tocopherol with peroxyl radicals, which represents the best understood biological activity of this vitamin.

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Section: Resultssupporting

confidence: 61%

Ultrafast Vibrational Spectroscopic Studies on the Photoionization of the α-Tocopherol Analogue Trolox C

et al. 2014

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“…The path integral calculations yield an absorption spectrum that is shifted to the blue by 0.34 eV relative to the experimental one (shown by the dashed curve in Figure 7b), which is centered at ≈ m E 1.7 eV. 32 Note that energy of the HOMO generally increases ( Figure 2S(b)) and the corresponding energy gaps between the HOMO and the lower unoccupied states decrease ( Figure 2S(c)) with the increasing radius of gyration. That is, the spread in these energies is largely accounted for by the variation in the cavity size.…”

Section: Energetics and The Absorption Spectrummentioning

confidence: 86%

“…In panels (b) and (d), we plotted the fits of our calculated CIS spectrum to a Gaussian-Lorentzian function that is typically used to approximate the experimental spectra of solvated electron: 32 …”

Section: Figure 5smentioning

confidence: 99%

The Structure of the Hydrated Electron. Part 2. A Mixed Quantum/Classical Molecular Dynamics Embedded Cluster Density Functional Theory: Single−Excitation Configuration Interaction Study

et al. 2007

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Adiabatic mixed quantum/classical (MQC) molecular dynamics (MD) simulations were used to generate snapshots of the hydrated electron in liquid water at 300 K. Water cluster anions that include two complete solvation shells centered on the hydrated electron were extracted from the MQC MD simulations and embedded in a roughly 18 Å x 18 Å x 18 Å matrix of fractional point charges designed to represent the rest of the solvent. Density functional theory (DFT) with the Becke-Lee-Yang-Parr functional and single-excitation configuration interaction (CIS) methods were then applied to these embedded clusters. The salient feature of these hybrid DFT(CIS)/MQC MD calculations is significant transfer (ca. 18%) of the excess electron's charge density into the 2p orbitals of oxygen atoms in OH groups forming the solvation cavity. We used the results of these calculations to examine the structure of the singly occupied and the lower unoccupied molecular orbitals, the density of states, the absorption spectra in the visible and ultraviolet, the hyperfine coupling (hfc) tensors, and the infrared (IR) and Raman spectra of these embedded water cluster anions. The calculated hfc tensors were used to compute the The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory ("Argonne"). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC-02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government. Electron Paramagnetic Resonance (EPR) and Electron Spin Echo Envelope Modulation(ESEEM) spectra for the hydrated electron that compared favorably to the experimental spectra of trapped electrons in alkaline ice. The calculated vibrational spectra of the hydrated electron are consistent with the red-shifted bending and stretching frequencies observed in resonance Raman experiments. In addition to reproducing the visible/near IR absorption spectrum, the hybrid DFT model also accounts for the hydrated electron's 190-nm absorption band in the ultraviolet. Thus, our study suggests that to explain several important experimentally observed properties of the hydrated electron, many-electron effects must be accounted for: one-electron models that do not allow for mixing of the excess electron density with the frontier orbitals of the first-shell solvent molecules cannot explain the observed magnetic, vibrational, and electronic spectroscopy of this species. Despite the need for multielectron effects to explain these important properties, the ensemble-averaged radial wavefunctions and energetics of the highest occupied and three lowest unoccupied orbitals of the hydrated electrons in our hybrid model are close to the s-and p-like states obtained in one-electron models. Thus, one-electron models can provide...

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“…27 Experiments with total excitation energies from 9.3 to 11.0 eV were performed at the University of Southern California, and measurements at 8.3 and 12.4 eV were made at Argonne National Laboratory. In the former experiments, corresponding to two-photon excitation from 267 to 225 nm, the excitation and probe laser pulses come from nonlinear frequency conversion of the 1 kHz output of a regeneratively amplified Ti:sapphire laser ͑Spectra Physics Hurricane͒.…”

Section: Methodsmentioning

confidence: 99%

Excitation-energy dependence of the mechanism for two-photon ionization of liquid H2O and D2O from 8.3to12.4eV

Elles

Jailaubekov

Crowell

et al. 2006

The Journal of Chemical Physics

119

192

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Transient absorption measurements monitor the geminate recombination kinetics of solvated electrons following two-photon ionization of liquid water at several excitation energies in the range from 8.3 to 12.4 eV. Modeling the kinetics of the electron reveals its average ejection length from the hydronium ion and hydroxyl radical counterparts and thus provides insight into the ionization mechanism. The electron ejection length increases monotonically from roughly 0.9 nm at 8.3 eV to nearly 4 nm at 12.4 eV, with the increase taking place most rapidly above 9.5 eV. We connect our results with recent advances in the understanding of the electronic structure of liquid water and discuss the nature of the ionization mechanism as a function of excitation energy. The isotope dependence of the electron ejection length provides additional information about the ionization mechanism. The electron ejection length has a similar energy dependence for two-photon ionization of liquid D 2 O, but is consistently shorter than in H 2 O by about 0.3 nm across the wide range of excitation energies studied.

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Temperature and isotope effects on the shape of the optical absorption spectrum of solvated electrons in water

Cited by 244 publications

References 9 publications

Ultrafast Vibrational Spectroscopic Studies on the Photoionization of the α-Tocopherol Analogue Trolox C

Ultrafast Vibrational Spectroscopic Studies on the Photoionization of the α-Tocopherol Analogue Trolox C

The Structure of the Hydrated Electron. Part 2. A Mixed Quantum/Classical Molecular Dynamics Embedded Cluster Density Functional Theory: Single−Excitation Configuration Interaction Study

Excitation-energy dependence of the mechanism for two-photon ionization of liquid H2O and D2O from 8.3to12.4eV

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