<i>Ab initio</i>complex Kohn calculations of dissociative excitation of water

Gil, T.J.; Rescigno, T. N.; McCurdy, C. W.; Lengsfield, Byron H.

doi:10.1103/physreva.49.2642

Cited by 47 publications

(98 citation statements)

References 19 publications

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“…In Fig. 3, at T = 20 eV, we can also compare the present DCS with a complex Kohn calculation from Gil et al 9 Here we find that the calculation systematically overestimates the magnitude of the measured DCS ͑by a factor of ϳ2͒ across the common angular range. On the other hand the shapes of the measured and calculated angular distributions are in very good accord.…”

Section: -5mentioning

confidence: 84%

“…One possible explanation for the discrepancy between the calculation and our measurements at 20 eV has been advanced by Rescigno. 59 He noted that the Ã 1 B 1 state is an example of a "Valberg" state, namely, it has both Rydberg and valence characters that would be very difficult to characterize properly with the relatively simple description of the target used by Gil et al 9 Another possibility might be that a fixed nuclei ͑FN͒ description for the scattering framework is inadequate, rather an adiabatic nuclei ͑AN͒ approach might be required. There is some anecdotal evidence in support of this latter proposition.…”

Section: -5mentioning

confidence: 99%

“…Indeed even a good description for the target states is nontrivial here. 9 In general, with some notable exceptions, most of the theory results report integral cross sections ͑ICSs͒ and there are significant quantitative differences found between the results from the different methods. This latter observation provides further impetus for the present work.…”

Section: Introductionmentioning

confidence: 99%

“…From a theoretical perspective there are, in fact, several calculations, using different methods, available in the literature for a small subset of the electronic states of H 2 O. These include the R-matrix calculations by Morgan 7 and Gorfinkiel et al 8 for the low-lying 3 B 1 , 1 B 1 , 3 A 1 , and 1 A 1 electronic states, the complex Kohn results by Gil et al 9 again for the same 3 B 1 , 1 B 1 , 3 A 1 , and 1 A 1 states, the distorted-wave Born calculations by Lee et al 10,11 for a couple of the 3 A 1 states, and a Schwinger multichannel method result, 12 also for the lowest-lying 3 A 1 electronic state. This apparent lack of comprehensive theoretical scattering work is not really surprising as water possesses both a strong permanent dipole moment and a significant dipole polarizability, which makes it a real challenge for current-state-ofthe-art scattering calculations.…”

Section: Introductionmentioning

confidence: 99%

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Cross sections and oscillator strengths for electron-impact excitation of the ÃB11 electronic state of water

Thorn

Brunger²,

Teubner³

et al. 2007

The Journal of Chemical Physics

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The authors report absolute differential and integral cross section measurements for electron-impact excitation of the ÃB11 electronic state of water. This is an important channel for the production of the OH (X̃Π2) radical, as well as for understanding the origin of the atmospheric Meinel [Astrophys. J. 111, 555 (1950)] bands. The incident energy range of our measurements is 20–200eV, while the angular range of the differential cross section data is 3.5°–90°. This is the first time such data are reported in the literature and, where possible, comparison to existing theoretical work, and new scaled Born cross sections calculated as a part of the current study, is made. The scaled Born cross sections are in good agreement with the integral cross sections deduced from the experimental differential cross sections. In addition they report (experimental) generalized oscillator strength data at the incident energies of 100 and 200eV. These data are used to derive a value for the optical oscillator strength which is found to be in excellent agreement with that from an earlier dipole (e,e) experiment and an earlier photoabsorption experiment.

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Section: -5mentioning

confidence: 84%

Section: -5mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cross sections and oscillator strengths for electron-impact excitation of the ÃB11 electronic state of water

Thorn

Brunger²,

Teubner³

et al. 2007

The Journal of Chemical Physics

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“…is a resonant process that involves the capture of a free electron into a transient negative ion state which subsequently dissociates to produce neutral and ionic fragments. Previous experimental [1][2][3][4][5][6][7][8][9][10] and theoretical studies [11][12][13][14][15][16][17][18][19] [9] observed the opening of the lower three-body channel, as discerned through the kinetic energy distribution of the O − fragment. However, because of the large O atom/H 2 mass ratio, such a measurement is difficult and a quantitative experimental determination of the final-state branching ratios among the two-and three-body breakup channels has yet to be published.…”

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confidence: 99%

Three-body breakup in dissociative electron attachment to the water molecule

2008

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We report the results of ab initio calculations on dissociative electron attachment (DEA) to water that demonstrate the importance of including three-body breakup in the dissociation dynamics. While three-body breakup is ubiquitous in the analogous process of dissociative recombination, its importance in low-energy dissociative electron attachment to a polyatomic target has not previously been quantified. Our calculations, along with our earlier studies of DEA into two-body channels, indicate that three-body breakup is a major component of the observed O − cross section. The local complex potential model provides a generally accurate picture of the experimentally observed features in this system, reproducing some quantitatively, others qualitatively, and one not at all.PACS numbers: 03.65. Nk, 34.80.Ht Dissociative electron attachment (DEA) to the water molecule, [9] observed the opening of the lower three-body channel, as discerned through the kinetic energy distribution of the O − fragment. However, because of the large O atom/H 2 mass ratio, such a measurement is difficult and a quantitative experimental determination of the final-state branching ratios among the two-and three-body breakup channels has yet to be published.There is strong reason to believe that three-body breakup is important for describing DEA leading to O − production. In particular, examination of the shape of the 2 A 1 surface suggests that three-body breakup may be the key to describing O − production via this resonance. The 2 A 1 (1 2 A ′ ) electronic surrface slopes downward toward linear H-O-H geometry and is dissociative along the OH bonds. It provides a path for symmetric dissociation of the OH bonds to produce O − + H + H, but also slopes downward toward the H − + OH asymptotes. Similarly, the 2 B 2 diabatic surface, which equals the 2 B 2 adiabatic surface for C 2v geometries, provides a path toward symmetric dissociation through the conical intersection with the 2 A 1 state. Symmetric dissociation of the 2 B 2 state from the equilibrium geometry of the neutral leads to the O − + H + H three-body asymptote.Our methodology is very similar to that used in our previous calculations, so we provide only a brief summary

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Electron Scattering by Atoms, Ions, and Molecules

Bartschat

Burke

Crowe

2009

Digital Encyclopedia of Applied Physics

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A summary is given of many important advances in the scattering of electrons from atoms, ions, and molecules up to the summer of 2008. Recently introduced experimental techniques, which lead to more efficient studies, are discussed together with a wide range of increasingly sophisticated theoretical methods. Examples of experimental and theoretical data are presented and compared where appropriate.

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Ab initiocomplex Kohn calculations of dissociative excitation of water

Cited by 47 publications

References 19 publications

Cross sections and oscillator strengths for electron-impact excitation of the ÃB11 electronic state of water

Cross sections and oscillator strengths for electron-impact excitation of the ÃB11 electronic state of water

Three-body breakup in dissociative electron attachment to the water molecule

Electron Scattering by Atoms, Ions, and Molecules

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