Intensity dependent geminate recombination in water

Long, Frederick H.; Lu, H. Peter; Shi, Xuelong; Eisenthal, Kenneth B.

doi:10.1016/0009-2614(91)80137-m

Cited by 56 publications

(53 citation statements)

References 49 publications

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“…This time constant, most likely, reflects the excited state lifetime in accord with previous reports. 20,25,31,40,44,47,49 A single-exponential fit to the remainder of the signal yields a decay of ∼110 fs. A rapidly decaying induced transparency and a slowly decaying induced absorption of hydrated electrons excited at 780 nm have been reported before.…”

Section: Methodsmentioning

confidence: 99%

Wave Packet Dynamics in Ultrafast Spectroscopy of the Hydrated Electron

et al. 1998

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Hydrated-electron dynamics is examined by frequency-resolved pump-probe experiments using pulses of 13 fs centered at 780 nm. A recurrence at ∼40 fs signifies a strong coupling of the electronic transition to underdamped solvent motions. Wave packet dynamics launched by the pump pulse produces an ultrafast red-shift of the electronic transition by approximately 6500 cm -1 . Gross features of the pump-probe experiments are analyzed using a two-level system.

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Section: Methodsmentioning

confidence: 99%

Wave Packet Dynamics in Ultrafast Spectroscopy of the Hydrated Electron

et al. 1998

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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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“…It is also possible that the previous data for 8 eV excitation overestimate the survival probability, and therefore the ejection length, in D 2 O due to a contribution from threephoton absorption or from solvent heating by the pump pulse. Pumping the sample with high power laser pulses in order to obtain good signal levels often produces these unwanted nonlinear effects, 13,34 especially at low excitation energies where the ionization yield is very small ͑Ͻ5%͒. 22 Nonlinear effects may have a more pronounced influence on the signal in D 2 O, because the ionization yield is smaller in that liquid than in H 2 O, 22 but the 300 nm excitation pulses in our experiment are too weak for us to test this hypothesis for an excitation energy of 8.3 eV.…”

Section: B Electron Ejection Length and Survival Probabilitymentioning

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

120

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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Intensity dependent geminate recombination in water

Cited by 56 publications

References 49 publications

Wave Packet Dynamics in Ultrafast Spectroscopy of the Hydrated Electron

Wave Packet Dynamics in Ultrafast Spectroscopy of the Hydrated Electron

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

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

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