Two-photon ionization and dissociation of liquid water by powerful laser UV radiation

Nikogosyan, David N.; Oraevsky, Alexander A.; Rupasov, Valery I.

doi:10.1016/0301-0104(83)85070-8

Cited by 249 publications

(239 citation statements)

References 16 publications

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“…Contrasting with the one-photon spectrum, which has a strong absorption maximum at 8.2 eV, the Ã band in the two-photon spectrum is much weaker than the second absorption band, with the two-photon spectrum decreasing by an order of magnitude or more in this region. 8,18 The relatively weak two-photon transition probability to the Ã state may originate from the atomic oxygen s ← p character of the excitation, even though the two-photon molecular transition is not strictly symmetry forbidden. 40 We are currently study- ing the ionization and dissociation yields in this region in an effort to clarify the nature of the excited state created by two-photon absorption at 8.3 eV.…”

Section: Discussionmentioning

confidence: 99%

“…6͒, 2 even though ionization occurs down to the onset for optical absorption at 6.5 eV or below. 7,8 A leading candidate for the ionization mechanism at very low excitation energies is proton-coupled electron transfer, where nuclear motion after molecular excitation allows the system to attain a favorable geometry for transferring the excited electron into a localized ͑trap͒ state below the conduction band of the liquid. Importantly, the proton-coupled electron transfer mechanism bypasses the conduction band of the liquid by ejecting the electron into a solvent trap.…”

Section: B Nature Of the Ionization Mechanism As A Function Of Energymentioning

confidence: 99%

“…1 Although several estimates place the threshold energy for vertical ionization of liquid water in the range of 8.5-10 eV or higher, [2][3][4][5][6] photoionization can occur for excitation energies as low as 6.5 eV. 7,8 This discrepancy implies that nuclear motion of the excited water molecule plays a key role in the ionization mechanism at low excitation energies, a͒ providing an alternate pathway for electron ejection that does not require direct ͑vertical͒ excitation into the conduction band of the liquid. 9 Several mechanisms have been proposed for excitation below the direct ionization threshold, but importantly, there is no clear and consistent picture of the ionization mechanism across this range of excitation energies.…”

Section: Introductionmentioning

confidence: 99%

“…13 Other experiments at excitation energies up to 10 eV support the observation that the ejection length increases rapidly above 9 -9.5 eV, 6,14-21 although there are substantial difficulties in comparing previous results due to different methods of reporting recombination yields and the use of different fitting procedures. Further complicating that comparison is the fact that only a few authors specifically examine the energy dependence of the ionization mechanism over a broad range of energies, 6,8,12,14,15,22 and that, with the exception of a recent study at 12.4 eV by one of our groups, 21 there are no reliable data for excitation energies above 10 eV.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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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Section: Discussionmentioning

confidence: 99%

Section: B Nature Of the Ionization Mechanism As A Function Of Energymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

View full text Add to dashboard Cite

show abstract

“…Absolute 2PA cross sections have been reported at a limited number of discrete energies. [42][43][44][45][46] Most notably, Nikogosyan et al 42 observed a monotonic rise of the cross section for degenerate two-photon excitation with a picosecond laser at five energies ranging from 7.8 to 9.3 eV. The increasing 2PA across that range strongly contrasts with the distinct absorption band at 8.3 eV in the 1PA spectrum.…”

Section: Introductionmentioning

confidence: 98%

Electronic structure of liquid water from polarization-dependent two-photon absorption spectroscopy

Elles¹,

Rivera²,

Zhang³

et al. 2009

The Journal of Chemical Physics

106

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Two-photon absorption ͑2PA͒ spectroscopy in the range from 7 to 10 eV provides new insight on the electronic structure of liquid water. Continuous 2PA spectra are obtained via the pump-probe technique, using broadband probe pulses to record the absorption at many wavelengths simultaneously. A preresonance enhancement of the absolute 2PA cross section is observed when the pump-photon energy increases from 4.6 to 6.2 eV. The absorption cross section also depends on the relative polarization of the pump and probe photons. The variation of the polarization ratio across the spectrum reveals a detailed picture of the 2PA and indicates that at least four different transitions play a role below 10 eV. Theoretical polarization ratios for the isolated molecule illustrate the value of the experimental polarization measurement in deciphering the 2PA spectrum and provide the framework for a simple simulation of the liquid spectrum. A more comprehensive model goes beyond the isolated molecule picture and connects the 2PA spectrum with previous one-photon absorption, photoelectron, and x-ray absorption spectroscopy measurements of liquid water. Previously unresolved, overlapping transitions are assigned for the first time. Finally, the electronic character of the vertical excited states is related to the energy-dependent ionization mechanism of liquid water.

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Interaction of Charged Particles with Molecular Medium and Track Effects in Radiation Chemistry

Kaplan

Miterev

1987

Advances in Chemical Physics

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Two-photon ionization and dissociation of liquid water by powerful laser UV radiation

Cited by 249 publications

References 16 publications

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

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

Electronic structure of liquid water from polarization-dependent two-photon absorption spectroscopy

Interaction of Charged Particles with Molecular Medium and Track Effects in Radiation Chemistry

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