Table of contents

Methylation effect has been observed and studied in electron-scattering from selected hydrocarbon molecules. In measured total cross section (TCS) functions we have noticed energy shifts and changes in the intensity of observed structures.

The robust Regge-pole methodology which embeds the crucial electron correlations and the vital core-polarization interaction is used to explore negative-ion formation in the actinide atoms Pu, Am and Lr through the electron elastic total cross sections (TCSs) calculation. The TCSs are found to be characterized by ground, metastable and excited anionic formation, whence we extract the anionic binding energies and compare them with existing electron affinities. The TCSs exhibit both atomic and molecular behavior in addition to polarization-induced metastable TCSs.

A complex optical potential (OP) is employed within the framework of the Dirac partial wave method to study the critical minima (CM) in the differential cross sections and the spin polarization for the elastic scattering of electrons by the Sr atom in the energy range E_i = 1-1000 eV. The complex optical potential is composed of the static, exchange, polarization and absorption potentials. The number of CM points has been found to be 7 in the DCSs of e-Sr scattering, while the number of maximum spin polarization points observed is 13.

Theoretical differential, elastic, total, momentum transfer, viscosity cross sections and spin-polarization for the elastic scattering of e^∓ by H₂ O molecule in the energy range 10 eV-10 keV have been calculated. These calculations have been carried out within the framework the Dirac partial wave analysis. We have employed a complex optical potential and additivity rule (AR) to compute the cross sections. Present results reasonably agree with available experimental data and other theoretical findings.

In some cases of the ion mobility measurements in cooled He gas, we have observed the separation of electronic states for small molecular ions. Both NH⁺ and ND⁺ show the separation of X²Π and a⁴Σ states. The meta-stable ${\mathrm{ND}}_{2}^{+}$ and ${\mathrm{NH}}_{3}^{+}$ were observed, but these of ${\mathrm{NH}}_{2}^{+}$ and ${\mathrm{ND}}_{3}^{+}$ do not appear in the measurements. The reason of the isotope dependence in mobility measurement is discussed using the calculated potential energy curves for ${\mathrm{NH}}_{2}^{+}$ and ${\mathrm{ND}}_{2}^{+}$.

We present experimental mass stopping powers of electrons in gaseous H₂ obtained with a newly developed electron time-of-flight spectrometer, for the incident electron energy range of 10 eV to 25 eV. In our procedure the average energy loss is derived from our conversion of measured electron time-of-flight spectra into equivalent electron energy loss spectra so as to obtain the values of mass stopping power for electron scattering from H₂.

We present experimental differential elastic scattering cross sections (DCSs) for low energy electron scattering from benzonitrile along with integral and momentum-transfer cross sections that are determined from these DCSs. The measurements of DCSs are obtained using the relative flow method with helium as the standard gas, in a crossed electron-molecular gas beam arrangement. Our measurements are made at incident electron energies in the range of 1 – 30 eV and scattering angles in the range of (10°-130°).

Here we investigate through the electron elastic total cross sections (TCSs) calculations the variation of the electron affinity (EA) with the fullerene size from C₄₄ to C₁₃₆ and contrast their EAs with that of C₆₀. The TCSs are found to be characterized generally by ground, metastable and excited anionic formation during the collisions. The extracted ground state anionic binding energies for C₄₄, C₇₄, C₁₀₀, C₁₂₄ and C₁₃₆ are 3.25eV, 4.03eV, 3.67eV, 3.06 eV and 3.75eV, respectively. These corresponding to the fullerenes EAs demonstrate their wide variation.

We reported elastic and excitation cross sections for electron collisions with methylene radical using R-matrix method for electron energies ranging from 0.01 to 15 eV in close-coupling (CC) approximation. We discuss the multi-channel-coupling effects on the calculated cross sections and resonances, and how the number of excited states included in the target state impacts the convergence of the elastic and the X³B₁ → 1¹A₁ and X³B₁ → 1¹B₁ excitation cross sections, especially at higher impact energy. Finally, we estimate the accuracy of the 1¹A₁and 1¹B₁ excitation cross sections.

We study Wigner time delay of slow electrons by spherically symmetric square potential well as a function of the well parameters. We show that the electron interaction with scattering center qualitatively depends on presence of discrete levels in the well. Electron retention mode by a potential well with no discrete level is replaced by the mode at which after level appears the incident electron hardly enters the scatterer. This behavior of time delay is universal since it is typical not only for the first but also for following arising s-levels.

We study theoretically the experimental angle-differential elastic electron scattering off a C₆₀ fullerene with the aim to elucidate whether its features depend primarily on the details of the full molecular potential of C₆₀ or they can be understood without reference to the full nature of the potential. We demonstrate the success of the latter option.

We have performed a combined experimental and theoretical study of electron elastic differential and integral cross sections from methane molecule (CH4) in the intermediate energy range. Data have been compared with available data sets in the literature as well as with recommended data set [Song et al J. Phys. Chem. Ref.Data44 023101 (2015)].

Electron attachment to molecular target can lead to a variety of negative fragment ions. We experimentally probe the main dissociative electron attachment channels in furan-2-carboxylic acid (C₃H₃O₂ – COOH) - a molecular target composed of two important structural units: a furan ring and a carboxylic group. In our studies we utilise nearly mono-energetic electrons at electron energies from 0 eV up to 15 eV. Our detection setup is based on extraction lens system and quadrupole mass spectrometer, that enables measurement of the energy dependent mass-selected yields of newly formed stable anions.

A new electron scattering apparatus is developed based on concepts from the positron system built by Surko et al. In an electron-version of the system, the electron beam is provided by a cathode and the rest of the system is correspondingly modified to a simpler system. The system was tested with argon to verify its operation. N₂O is important in atmosphere and plasma, and in the intermediate energy region, there are two previous results which are in disagreement. We present here a result for the total electron cross section of N₂O.

We employed both eletronic scattering techniques and ab initio quantum dynamics to study electron-driven reactions in halouracils at low energies. Particularly, it was addressed halogen dissociation and H-loss probabilities in anionic 5-BrU and 5-IU. Besides, we also propose a model of how to include auto-ionization probabilities during the dynamics.

Experimental differential cross sections for low energy electron scattering from trichloromethane is measured utilizing a crossed electron-molecular beam experiment via the relative flow method, for the incident electron energies in the range of E₀ = 0.5eV-30eV and the scattering angles in the range of θ = 10° – 130°.

Total cross section for electron scattering from SnCl₄ molecules has been measured for energies from 0.6 to 300 eV. Obtained results have been compared with total cross sections for electron scattering from other tetrachoride molecules: XCl₄ where X=C, Si, Ge.

We present a study on the electron transmission and dissociative electron attachment asymmetries in halocamphor species. Our results consist in their anion state spectra, applied in a model for the spin-polarized electron scattering problem under the influence of a low energy resonance.

Electron impact scattering studies with organic compounds play a significant role in studies related to astrophysics and radiation physics. We present here electron impact scattering studies on formyl fluoride as no cross-sectional data is available to the best of our knowledge. Total scattering cross sections (TCS) on comparing with iso-electronic molecule reveals that at low energy molecular dipole moment plays a significant role in cross-section deviation and at high energy the tendency seems to be same in all the formyl series.

In the present case we study the electron impact scattering cross sections on diborane (B₂H₆) for the energy range 0.1 eV to 5000 eV. The present study provides differential cross sections (DCS), momentum transfer cross sections (MTCS), ionization cross sections and total scattering cross sections (TCS). The experimental determinations of these cross sections are rather difficult dur to its complex structure and stability. These cross sections are important in many applied fields.

The demand for electron-impact cross sections has increased tremendously in recent years. There is, however, a special interest in such cross sections for hydrogen molecules and its isotopomers, HD and D₂. We have computed target properties & electron scattering cross sections for H₂, HD and D₂ and discuss different phenomena and their importance.

We carefully investigate negative ion formation in the large lanthanide atoms Ho, Er, Tm, Yb and Lu as well as in atomic Hf through the electron elastic total cross sections (TCSs) calculation using the robust Regge-pole methodology. The TCSs are found to be characterized generally by ground, metastable and excited states negative ion formation. The extracted from the TCSs anionic binding energies (BEs), with those for the ground states corresponding to the definitive and unambiguous electron affinities (EAs), are contrasted with the measured and/or calculated EAs.