Low-energy electron elastic scattering from complex atoms: Nd, Eu, and Tm

The recent Regge-pole methodology, which includes the essential electron correlations, is employed together with a Thomas–Fermi type potential incorporating the vital core-polarization interaction to calculate low-energy (E less than or equal to 1 eV) electron elastic total and Mulholland cross sections for the complex atoms Nd, Eu, and Tm, found to be characterized by subtle Regge resonances, for a fundamental understanding of the mechanism of the near-threshold electron attachment. The binding energies of the complex negative ions Nd–, Eu–, and Tm– formed through the collisions as Regge resonances are extracted for the first time from the resonances and compared with the latest theoretical and experimental values. Ramsauer–Townsend minima, shape resonances, and the Wigner threshold behavior are also obtained.

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Fullerene Negative Ions: Formation and Catalysis

10.20944/preprints202002.0420.v1 ◽

2020 ◽

Author(s):

Zineb Felfli ◽

Kelvin Suggs ◽

Nantambu Nicholas ◽

Alfred Z. Msezane

Keyword(s):

Transition State ◽

Cross Sections ◽

Water Oxidation ◽

Regge Pole ◽

Negative Ions ◽

Negative Ion ◽

Total Cross Sections ◽

Hydrogen Bond Strength ◽

Low Energy Electron ◽

Fundamental Mechanism

We first explore negative-ion formation in fullerenes C44, C60, C70, C98, C112, C120, C132 and C136 through low-energy electron elastic scattering total cross sections calculations using our Regge-pole methodology. Water oxidation to peroxide and water synthesis from H2 and O2 are then investigated using the anionic catalysts C44ˉ to C136ˉ. The fundamental mechanism underlying negative-ion catalysis involves hydrogen bond strength-weakening in the transition state. DFT transition state calculations found C60ˉ numerically stable for both water and peroxide synthesis, C100ˉ increases the energy barrier the most and C136ˉ the most effective catalyst in both water synthesis and oxidation to H2O2.

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Взаимодействие низкоэнергетических электронов с молекулами D-рибозы

Оптика и спектроскопия ◽

10.21883/os.2021.12.51732.2580-21 ◽

2021 ◽

Vol 129 (12) ◽

pp. 1471

Author(s):

И.В. Чернышова ◽

Е.Э. Контрош ◽

О.Б. Шпеник

Keyword(s):

Total Cross Section ◽

Energy Range ◽

Cross Section ◽

Electron Scattering ◽

Cross Sections ◽

Electron Attachment ◽

Low Energy ◽

Dissociative Electron Attachment ◽

Low Energy Electrons ◽

First Time

Abstract– The interactions of low-energy electrons (<20 eV) with D-ribose molecules, namely, electron scattering and dissociative attachment, are studied. The results of these studies showed that the fragmentation of D-ribose molecules occurs effectively even at an electron energy close to zero. as well as in the energy range 5.50–9.50 eV. In the total cross section of electron scattering by molecules, resonance features at energies of 5.00–9.00 eV in the region of formation of ionic fragments C3H4O2–, C2H3O2–, OH–, associated with the destruction of molecular heterocycles, were experimentally discovered for the first time. The correlation of the features observed in the scattering and dissociative electron attachment cross sections is analyzed.

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Microsecond dynamics of molecular negative ions formed by low-energy electron attachment to fluorinated tetracyanoquinodimethane

The Journal of Chemical Physics ◽

10.1063/5.0072264 ◽

2021 ◽

Vol 155 (18) ◽

pp. 184301

Author(s):

Stanislav A. Pshenichnyuk ◽

Alberto Modelli ◽

Nail L. Asfandiarov ◽

Rustam G. Rakhmeyev ◽

Aleksey M. Safronov ◽

...

Keyword(s):

Electron Attachment ◽

Negative Ions ◽

Low Energy ◽

Energy Electron ◽

Low Energy Electron

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Laboratory studies of electron attachment and detachment processes of aeronomic interest

Canadian Journal of Chemistry ◽

10.1139/v69-289 ◽

1969 ◽

Vol 47 (10) ◽

pp. 1783-1793 ◽

Cited By ~ 103

Author(s):

A. V. Phelps

Keyword(s):

Cross Sections ◽

Ion Beam ◽

Electron Attachment ◽

Negative Ions ◽

High Energy ◽

Low Energy ◽

Rate Coefficients ◽

Dissociative Attachment ◽

Three Body ◽

Energy Processes

Techniques for the study of electron attachment and detachment are reviewed. The rate coefficients for the various processes of aeronomic interest are then discussed. The rates of three-body and dissociative attachment by thermal electrons have been successfully determined by swarm techniques and by high frequency studies of electrons produced by high energy particles and by photoionization. Collisional and associative detachment rates for thermal energy negative ions have been measured using the swarm and flowing afterglow techniques. Radiative attachment rates for some atmospheric negative ions have been calculated from measurements of photodetachment cross sections using crossed photon and ion beam techniques. Electron beam studies and measurements of ion kinetic energy have provided much useful information regarding the dissociative attachment process and the structure of molecular negative ions. Rate coefficients for low energy processes such as the three-body attachment to O2, the radiative attachment to O, and the associative detachment of O− in collisions with various atmospheric gases are reasonably well known. Other possibly important low energy processes, such as dissociative attachment to O3, radiative attachment to O2, and the associative detachment of O2− are less well known.

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Negative Ion Formation in Low-Energy Electron Collisions with the Actinide Atoms Th, Pa, U, Np and Pu

Applied Physics Research ◽

10.5539/apr.v11n1p52 ◽

2019 ◽

Vol 11 (1) ◽

pp. 52 ◽

Cited By ~ 4

Author(s):

Zineb Felfli ◽

Alfred Z. Msezane

Keyword(s):

Theoretical Calculations ◽

Regge Pole ◽

Binding Energies ◽

Low Energy ◽

Energy Electron ◽

Negative Ion ◽

Electron Affinities ◽

Electron Collisions ◽

Ion Formation ◽

Low Energy Electron

Here we investigate ground and metastable negative ion formation in low-energy electron collisions with the actinide atoms Th, Pa, U, Np and Pu through the elastic total cross sections (TCSs) calculations. For these atoms, the presence of two or more open d- and f- subshell electrons presents a formidable computational task for conventional theoretical methods, making it difficult to interpret the calculated results. Our robust Regge pole methodology which embeds the crucial electron correlations and the vital core-polarization interaction is used for the calculations. These are the major physical effects mostly responsible for stable negative ion formation in low-energy electron scattering from complex heavy systems. We find that the TCSs are characterized generally by Ramsauer-Townsend minima, shape resonances and dramatically sharp resonances manifesting ground and metastable negative ion formation during the collisions. The extracted from the ground states TCSs anionic binding energies (BEs) are found to be 3.09eV, 2.98eV, 3.03eV, 3.06eV and 3.25eV for Th, Pa, U, Np and Pu, respectively. Interestingly, an additional polarization-induced metastable TCS with anionic BE value of 1.22eV is generated in Pu due to the size effect. We also found that our excited states anionic BEs for several of these atoms compare well with the existing theoretical electron affinities including those calculated using the relativistic configuration-interaction method. We conclude that the existing theoretical calculations tend to identify incorrectly the BEs of the resultant excited anionic states with the electron affinities of the investigated actinide atoms; this demonstrates the great need for experimental verification and unambiguous determination of their electron affinities.

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Low energy (6–18 eV) electron scattering from condensed thymidine (dT) III: absolute electronic excitation cross sections

Physical Chemistry Chemical Physics ◽

10.1039/d0cp00198h ◽

2020 ◽

Vol 22 (16) ◽

pp. 8364-8372

Author(s):

V. Lemelin ◽

A. D. Bass ◽

L. Sanche

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Cross Sections ◽

Electronic Excitation ◽

Low Energy ◽

Resolution Electron ◽

Excitation Cross Sections ◽

Low Energy Electron ◽

First Time ◽

Electron Energy Loss

We report for the first time the low-energy electron energy loss spectrum for electronic excitation of condensed thymidine measured by high resolution electron energy loss spectroscopy.

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Low-Energy Electron Elastic Total Cross Sections for Ho, Er, Tm, Yb, Lu, and Hf Atoms

Atoms ◽

10.3390/atoms8020017 ◽

2020 ◽

Vol 8 (2) ◽

pp. 17

Author(s):

Zineb Felfli ◽

Alfred Z. Msezane

Keyword(s):

Cross Sections ◽

Regge Pole ◽

Binding Energies ◽

Negative Ion ◽

Ion Binding ◽

Electron Affinities ◽

Total Cross Sections ◽

Ion Formation ◽

Electron Correlation Effects ◽

Low Energy Electron

The robust Regge-pole methodology wherein is fully embedded the essential electron-electron correlation effects and the vital core polarization interaction has been used to explore negative ion formation in the large lanthanide Ho, Er, Tm, Yb, Lu, and Hf atoms through the electron elastic total cross sections (TCSs) calculations. These TCSs are characterized generally by dramatically sharp resonances manifesting ground, metastable, and excited negative ion formation during the collisions, Ramsauer-Townsend minima, and shape resonances. The novelty and generality of the Regge-pole approach is in the extraction of the negative ion binding energies (BEs) of complex heavy systems from the calculated electron TCSs. The extracted anionic BEs from the ground state TCSs for Ho, Er, Tm, Yb, Lu, and Hf atoms are 3.51 eV, 3.53 eV, 3.36 eV, 3.49 eV, 4.09 eV and 1.68 eV, respectively. The TCSs are presented and the extracted from the ground; metastable and excited anionic states BEs are compared with the available measured and/or calculated electron affinities. We conclude with a remark on the existing inconsistencies in the meaning of the electron affinity among the various measurements and/or calculations in the investigated atoms and make a recommendation to resolve the ambiguity.

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Low-Energy Electron Elastic Collisions with Actinide Atoms Am, Cm, Bk, Es, No and Lr: Negative-Ion Formation

Atoms ◽

10.3390/atoms9040084 ◽

2021 ◽

Vol 9 (4) ◽

pp. 84

Author(s):

Alfred Z. Msezane ◽

Zineb Felfli

Keyword(s):

Cross Sections ◽

Regge Pole ◽

Binding Energies ◽

Negative Ion ◽

Shape Resonance ◽

Ion Binding ◽

Total Cross Sections ◽

Ion Formation ◽

Molecular Behavior ◽

Low Energy Electron

The rigorous Regge-pole method is used to investigate negative-ion formation in actinide atoms through electron elastic total cross sections (TCSs) calculation. The TCSs are found to be characterized generally by negative-ion formations, shape resonances and Ramsauer-Townsend(R-T) minima, and they exhibit both atomic and fullerene molecular behavior near the threshold. Additionally, a polarization-induced metastable cross section with a deep R-T minimum is identified near the threshold in the Am, Cm and Bk TCSs, which flips over to a shape resonance appearing very close to the threshold in the TCSs for Es, No and Lr. We attribute these new manifestations to size effects and orbital collapse significantly impacting the polarization interaction. From the TCSs unambiguous and reliable ground, metastable and excited states negative-ion binding energies (BEs) for Am−, Cm−, Bk−, Es−, No− and Lr− anions formed during the collisions are extracted and compared with existing electron affinities (EAs) of the atoms. The novelty of the Regge-pole approach is in the extraction of the negative-ion BEs from the TCSs. We conclude that the existing theoretical EAs of the actinide atoms and the recently measured EA of Th correspond to excited anionic BEs.

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