Ana Isabel Lozano

Total electron scattering cross sections (TCSs) for NO₂ molecules have been measured with a magnetically confined electron beam transmission apparatus for impact energies ranging from 1 to 200 eV. The estimated total uncertainty limits are within ±5%. Moreover, integral elastic, ionization, electronic and rotational excitation cross sections in the (20–1000 eV) energy range have been calculated with our independent atom model-based screening corrected additivity rule including interference effects (IAM-SCAR+I) method. The cross-section data set derived from this study is critically compared with the recommended values available in the literature.

The first VUV absorption spectrum of 2-chloropyrimidine compared with that of pyrimidine shows that halogen effects grow with energy. TDDFT with the nuclear ensemble method closely matches experiment, outperforming the simpler vertical approximation.

We report novel total electron scattering cross sections (TCS) from nitric oxide (NO) in the impact energy range from 1 to 15 eV by using a magnetically confined electron transmission apparatus. The accuracy of the data to within 5% and its consistency across the energy range investigated, shows significant discrepancies from previous works as to the major resonance features and magnitude of the TCS. Within the shape of the TCS, we have identified nine features which have been assigned to electron attachment resonances, most of them reported for the first time, while a comprehensive analysis of those peaking at 7.0, 7.8, and 8.8 eV has led to solve the controversy about dissociative electron attachment (DEA) cross-section that persisted for more than 50 years.

Total electron scattering cross sections (TCSs), in the energy range of 1–100 eV, have been measured with a high-resolution magnetically confined electron transmission apparatus, with total uncertainty limits estimated to be within ±5%. No previous experimental TCS data have been found for comparison. Electron attachment resonances, corresponding to transient negative ion formation, have been identified for energies below 20 eV by analyzing their contribution to the measured local maxima of the TCSs. Most of these resonances were observed for the first time. By means of our screening-corrected additivity rule (including interference effects) calculation method (IAM-SCAR + I), we extended TCS values to up to 1000 eV. This method also provides integral elastic, electronic excitation, and ionization cross sections for impact energies above 20 eV with total uncertainties of about ±10%. Comparisons, where possible, of the present electron scattering values with other values available in the literature are given.

A novel gas-phase molecular scattering study is reported for O2− collisions with CO2 for impact energies ranging from 50 to 950 eV in the lab frame. The absolute total electron detachment, relative total, and partial ionization cross sections have been measured within this energy range together with the positive ion yields. The primary anionic beam projectile is produced in a pulsed hollow cathode discharge induced plasma, and its interactions with the neutral molecular target occur in a gas cell at a well-known constant pressure. For impact energies above 500 eV, high mass (m > 44 u) charged complexes have been detected. With the aid of a theoretical study using ab initio methods, we propose a mechanism to infer the formation of these cationic species, which have been assigned to projectile–target stable compounds (CO3+ and CO4+).

Dissociative electron transfer in collisions between neutral potassium atoms and neutral ethanol molecules yields mainly OH⁻, followed by C₂H₅O⁻, O⁻, CH₃⁻ and CH₂⁻. The dynamics of negative ions have been investigated by recording time‐of‐flight mass spectra in a wide range of collision energies from 17.5 to 350 eV in the lab frame, where the branching ratios show a relevant energy dependence for low/intermediate collision energies. The dominant fragmentation channel in the whole energy range investigated has been assigned to the hydroxyl anion in contrast to oxygen anion from dissociative electron attachment (DEA) experiments. This result shows the relevant role of the electron donor in the vicinity of the temporary negative ion formed allowing access to reactions which are not thermodynamically attained in DEA experiments. The electronic state spectroscopy of such negative ions, was obtained from potassium cation energy loss spectra in the forward scattering direction at 205 eV impact energy, showing a prevalent Feshbach resonance at 9.36±0.10 eV with character, while a less pronounced contribution assigned to a shape resonance has been obtained at 3.16±0.10 eV. Quantum chemical calculations for the lowest‐lying unoccupied molecular orbitals in the presence of a potassium atom have been performed to support the experimental findings.

Electron induced dissociation of condensed benzene (C ₆ H ₆ ) in thin films on a Pt substrate is investigated by the electron stimulated desorption of anions and cations. Desorption yields and effective dipolar dissociation cross-sections are obtained.

Accurate total cross sections (TCS), within 5%, for electron scattering by N₂O 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 N₂O collisional database may help to improve the accuracy of radiation-induced transport models.