Femtosecond studies of hydrated electron recombination following multiphoton ionization at 390 nm

McGowen, J. L.; Ajo, H.M.; Zhang, J.Z.; Schwartz, Benjamin J.

doi:10.1016/0009-2614(94)01281-4

Cited by 55 publications

(77 citation statements)

References 25 publications

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“…1,7,8,9 Such changes have been observed by several ultrafast spectroscopy groups, including this laboratory. In particular, Crowell and Bartels 1,2 demonstrated that rapid geminate kinetics of hydrated electrons observed in three 400 nm photon ionization of water becomes slower and the fraction of escaped electrons increases when the radiance of the 400 nm light is in the terawatt range.…”

Section: Introductionmentioning

confidence: 93%

Light-Induced Temperature Jump Causes Power-Dependent Ultrafast Kinetics of Electrons Generated in Multiphoton Ionization of Liquid Water

et al. 2004

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Picosecond geminate recombination kinetics for electrons generated by multiphoton ionization of liquid water become power dependent when the radiance of the excitation light is greater than 0.3-0.5 TW/cm 2 (the terawatt regime). To elucidate the mechanism of this power dependence, tri-400 nm photon ionization of water has been studied using pump-probe laser spectroscopy on the pico-and femtosecond time scales.We suggest that the observed kinetic transformations are caused by a rapid temperature jump in the sample. Such a jump is inherent to multiphoton ionization in the terawatt regime, when the absorption of the pump light along the optical path becomes very nonuniform. The heating of water is substantial (tens of o C) because the 3-photon quantum yield of the ionization is relatively low, ca. 0.42, and a large fraction of the excitation energy is released into the solvent bulk as heat. Evidence of the temperature jump is the observation of a red shift in the absorption spectrum of (thermalized) electron 2 and by characteristic "flattening" of the thermalization dynamics in the near IR. The temperature jump in the terawatt regime might be ubiquitous in multiphoton ionization in molecular liquids. The implications of these observations for femtosecond pulse radiolysis of water are discussed.

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Section: Introductionmentioning

confidence: 93%

Light-Induced Temperature Jump Causes Power-Dependent Ultrafast Kinetics of Electrons Generated in Multiphoton Ionization of Liquid Water

et al. 2004

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“…To appreciate the system in full, it is vital to understand the initial steps from the photodetachment to the e − aq formation. Femtosecond pump-probe experiments have been used to unravel details of the equilibration processes following the trapping by the solvent [5][6][7][8][9][10][11][12]. In addition, picosecond measurements on the recombination kinetics of e − aq have described the ejected electron's migration lengths from its geminate partners [13][14][15][16][17][18][19][20][21][22].…”

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confidence: 99%

Direct observation of the collapse of the delocalized excess electron in water

et al. 2014

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It is generally assumed that the hydrated electron occupies a quasi-spherical cavity surrounded by only a few water molecules in its equilibrated state. However, in the very moment of its generation, before water has had time to respond to the extra charge, it is expected to be significantly larger in size. According to a particle-in-a-box picture, the frequency of its absorption spectrum is a sensitive measure of the initial size of the electronic wavefunction. Here, using transient terahertz spectroscopy, we show that the excess electron initially absorbs in the far-infrared at a frequency for which accompanying ab initio molecular dynamics simulations estimate an initial delocalization length of 40 Å. The electron subsequently shrinks due to solvation and thereby leaves the terahertz observation window very quickly, within 200 fs.

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“…[34][35][36][37][38][39]), geminate decay of the electron generated in rxn. (25) proceeds mainly via.…”

Section: B Concentration Effects and Ctts Photophysicsmentioning

confidence: 99%

Ultrafast dynamics for electron photodetachment from aqueous hydroxide

Crowell

Lian

Shkrob

et al. 2004

The Journal of Chemical Physics

105

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Charge-transfer-to-solvent (CTTS) reactions of hydroxide induced by 200 nm monophotonic or 337 nm and 389 nm biphotonic excitation of this anion in aqueous solution have been studied by means of pump-probe ultrafast laser spectroscopy. Transient absorption kinetics of the hydrated electron, e aq -, have been observed, from a few hundred femtoseconds out to 600 ps, and studied as function of hydroxide concentration and temperature. The geminate decay kinetics are bimodal, with a fast exponential component (ca. 13 ps) and a slower power "tail" due to the diffusional escape of the electrons. For the biphotonic excitation, the extrapolated fraction of escaped electrons is 1.8 times higher than for the monophotonic 200 nm excitation (31% vs. 17.5% at 25 o C, respectively), due to the broadening of the electron distribution. The biphotonic electron detachment is very inefficient; the corresponding absorption coefficient at 400 nm is < 4 cm TW -1 M -1 (assuming unity quantum efficiency for the photodetachment).

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Femtosecond studies of hydrated electron recombination following multiphoton ionization at 390 nm

Cited by 55 publications

References 25 publications

Light-Induced Temperature Jump Causes Power-Dependent Ultrafast Kinetics of Electrons Generated in Multiphoton Ionization of Liquid Water

Light-Induced Temperature Jump Causes Power-Dependent Ultrafast Kinetics of Electrons Generated in Multiphoton Ionization of Liquid Water

Direct observation of the collapse of the delocalized excess electron in water

Ultrafast dynamics for electron photodetachment from aqueous hydroxide

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