Electron-induced double ionization of isolated water molecules

Oubaziz, D.; Champion, C.; Aouchiche, H.

doi:10.1103/physreva.88.042709

Cited by 11 publications

(12 citation statements)

References 52 publications

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“…There could be other processes leading to water double ionization, in addition to that formed by soft X-rays via Auger decay. One such process is the electron impact double ionization, which has been studied theoretically in liquid water . Calculated double over single ionization cross sections ratios allow a rough estimate of the electron impact double ionization contribution in the liquid phase.…”

Section: Results and Discussionmentioning

confidence: 99%

“…One such process is the electron impact double ionization, which has been studied theoretically in liquid water. 48 Calculated double over single ionization cross sections ratios allow a rough estimate of the electron impact double ionization contribution in the liquid phase. This results in a total of two double ionizations per 1620 eV photon absorbed (one through K-shell photoabsorption and the other through electron impact).…”

Section: Irradiationmentioning

confidence: 99%

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Superoxide Production under Soft X-ray Irradiation of Liquid Water

et al. 2023

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Soft X-rays behave like particles with high linear energy transfer, as they deposit a large amount of their energy in the nanometric range, triggered by inner-shell ionization. In water, this can lead to the formation of a doubly ionized water molecule (H2O2+) and the emission of two secondary electrons (photoelectron and Auger electron). Our focus lies on detecting and quantifying the superoxide (HO2°) production via the direct pathway, i.e., from the reaction between the dissociation product of H2O2+, i.e., the oxygen atom (∼4 fs), and the °OH radicals present in the secondary electron tracks. The HO2° yield for 1620 eV photons, via this reaction pathway, was found to be 0.005 (±0.0007) μmol/J (formed within the ∼ps range). Experiments were also performed to determine the yield of HO2° production via another (indirect) pathway, involving solvated electrons. The indirect HO2° yield, measured experimentally as a function of photon energy (from 1700 to 350 eV), resulted in a steep decrease at around 1280 eV and a minimum close to zero at 800 eV. This behavior in contradiction with the theoretical prediction reveals the complexity hidden in the intratrack reactions.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Irradiationmentioning

confidence: 99%

Superoxide Production under Soft X-ray Irradiation of Liquid Water

et al. 2023

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“…However, special precautions must be taken for specific applications focused on energy loss and stopping powers, where multiple ionization processes become relevant for increasing energies. 35 Although the integral cross section analysis does not intend to reach the level of describing the induced (positive, negative, and neutral) fragmentation by electron impact, it is interesting to note that most of the references cited in Figure 6 provide partial ionization cross section (PICS) data for positive fragments. A complete summary of these results is found in Song et al's 13 review.…”

Section: Ionization Cross Sectionsmentioning

confidence: 99%

Integral Electron Scattering Cross Sections from N₂O for Impact Energies Ranging from 1 to 1000 eV

Lozano,

Rosado,

Blanco

et al. 2024

J. Phys. Chem. A

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Accurate total cross sections (TCS), within 5%, for electron scattering by N 2 O molecules have been measured with a magnetically confined electron transmission apparatus for impact energies ranging from 1 to 200 eV. For higher energies, these measurements have been complemented with our independent atom-based screening corrected additivity rule, including interference (IAM-SCAR + I) method to determine a complete reference TCS data set in the energy range (1−1000 eV). After a critical discussion that includes our calculated integral elastic and ionization cross sections and the theoretical and experimental data available in the literature, a complete set of integral elastic and inelastic (rotational, vibrational, and electronic excitation, ionization and electron attachment) cross sections, consistent with the reference TCS data, have been derived. This update on the N 2 O collisional database may help to improve the accuracy of radiationinduced transport models.

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“…[23]). Let us remark here that similarly to our previous works, we use here the single-center orientation-dependent description of the water molecule provided by Moccia [33] where the ten bound electrons of the water target molecule are distributed among Norb(= 5) molecular wave functions corresponding to the five molecular orbitals denoted 1 b 1 , 3a 1 ,1 b2, 2a 1 , and 1 a 1 .…”

mentioning

confidence: 93%

“…More recently, Montenegro and co-workers published a series of works [15][16][17] where fragmentation branching ratios of multiply charged water molecules have been analyzed in order to propose a general scheme for the fission and autodissociation processes of doubly charged water molecules. On the theoretical front, the situation is more critical since with the works of Dal Capello and co-workers, who successively treated the DI process within the first and second Born approximation [18][19][20], our recent publications [21,22] appear as the only one existing theoretical support for the electron-induced DI process of water molecules with, in particular, a detailed analysis in terms of angular and energy distributions of the ejected electrons as well as total cross sections for single oriented water molecules [23],The aim of the present work is to go beyond this series of orientation-dependent studies and then to report a theoretical description of the double ionization process for isolated water molecules in considering all the final water target configurations, namely, the two-electron removal from …”

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confidence: 98%

H2Odouble ionization induced by electron impact

2015

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Double ionization of water molecules remains, still today, rarely investigated on both the experimental and the theoretical side. In this context, the present work reports on a quantum mechanical approach providing a quantitative description of the electron-induced double ionization process on isolated water molecules for impact energies ranging from the target ionization threshold up to about 10 keV. The cross section calculations are here performed within the first Born approximation framework in which the initial state of the system includes a molecular ground-state wave function expressed as a single-center linear combination of atomic orbitals while the final state of the system is characterized by two independent Coulomb wave functions used for describing the two ejected electrons coupled by a Gamov factor used for modeling the electron-electron repulsion. Besides, in order to go beyond the first Born approximation, the scattered electron is considered as a particle being in the Coulomb field of the nucleus-whose charge is screened by the ejected electrons-and then treated by an approximate Coulomb wave function. In this perturbative-type description, let us add that the passive (not ionized) electrons are considered as frozen in their molecular orbitals during the collision which permits to reduce the electron-target interaction potential to a two-active-electron problem. Comparisons with rare available experimental data are reported as well an energetic analysis in terms of mean secondary energy transfer during the double ionization process in order to demonstrate the relevance of the electron-induced double ionization process.Electron-induced interactions in water are of great impor tance in many fields of research ranging from astrophysics to cellular biology with significant impacts in radiobiology, med ical imaging, and radiotherapy, essentially due to the fact that water is commonly used as a surrogate of the living matter. In this context, it is nowadays well recognized that the "physics" stage that takes place at the first postirradiation femtoseconds plays a key role in the avalanche of events occurring throughout the water radiolysis and then appears as a decisive step in the induction of the radiation cellular damages [1], Under these conditions, accurate cross sections-related to the different electron-induced interactions on water molecules-appear as crucial input data for the numerical codes devoted to the electron track-structure description in biological matter [2]. In this context, the single collisional processes induced by electron impact in water (including the elastic and inelastic channels) have been intensively investigated on both the theo retical [3,4] and the experimental [5,6] sides. Comparatively, the electron-impact double ionization (DI) of water molecules is less documented and therefore generally neglected in the majority of existing numerical track-structure codes arguing a presupposed minor contribution in the total energy deposit pattern. However, whether it is in the wat...

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Electron-induced double ionization of isolated water molecules

Cited by 11 publications

References 52 publications

Superoxide Production under Soft X-ray Irradiation of Liquid Water

Superoxide Production under Soft X-ray Irradiation of Liquid Water

Integral Electron Scattering Cross Sections from N₂O for Impact Energies Ranging from 1 to 1000 eV

H2Odouble ionization induced by electron impact

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Electron-induced double ionization of isolated water molecules

Cited by 11 publications

References 52 publications

Superoxide Production under Soft X-ray Irradiation of Liquid Water

Superoxide Production under Soft X-ray Irradiation of Liquid Water

Integral Electron Scattering Cross Sections from N2O for Impact Energies Ranging from 1 to 1000 eV

H2Odouble ionization induced by electron impact

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Integral Electron Scattering Cross Sections from N₂O for Impact Energies Ranging from 1 to 1000 eV