The perfluoronitrile C4F7N is considered a promising SF6-alternative in high-voltage gas-insulated apparatus, thanks to its high dielectric strength and low global warming potential. However, a complete and consistent set of electron-neutral collision cross-sections of C4F7N is still lacking, which hinders relevant plasma modelling. In this contribution, the available electron-neutral collision cross-sections of C4F7N are first compiled and assessed. The initial cross-sections are adjusted iteratively by the electron swarm method to determine a complete and self-consistent cross-section set of C4F7N for the first time. The set is validated by a systematic comparison of electron swarm parameters between Boltzmann equation analysis and experimental measurements in pure C4F7N as well as C4F7N/N2 and C4F7N/Ar mixtures. The proposed cross-section set of C4F7N will be made available to the community in the LXCat database. It will be of particular importance for applications with an emphasis on the discharge mechanisms of this novel gas.

Electron collision with liquid water is theoretically investigated and reported in this article. The range of projectile energy considered is 10−5000 eV, covering all major channels, viz., ionization, inelastic, elastic, and total scattering. The liquid phase electron charge density and static potential are generated and used in the calculation under a spherical complex optical potential formalism to achieve the goals. For the ionization channel, the complex scattering potentialionization contribution method is used. The agreement with available theoretical data is satisfactory. The study on the total electron scattering from liquid water, using a common method for elastic and inelastic cross sections, is new and requires further attempts to support the reported data.

We have chosen five complex molecules (C3F6O, C4F8O, C5F10O, C6F12O and C4F7N) for the present investigation, which are considered as potential substitutes for SF6 in plasma applications. There are some theoretical data available for ionization cross sections with contradicting values, especially at the peak. To the best of our knowledge, no experimental data are found in the literature to validate previous calculations. In this work, we have efficiently included nuclear charge distribution and the corresponding electrostatic potential in the spherical complex optical potential formalism for the first time. Thus, the nuclear static effect is included in the calculation of inelastic cross section of these plasma relevant molecules by electron scattering. A complex scattering potential-ionization contribution method is used to derive the ionization cross section. We have done a test run of the adopted changes on targets for which experimental measurements are available. Excellent agreement can be found for the entire energy range. For present plasma relevant molecules, a notable difference is seen in the lower energy region of investigation, which is a major improvement in our calculation. However, beyond the peak, the values are consistent with previous methods. For C6F12O this is the first report of ionization cross section.

Positron impact scattering cross-sections for pyridine and pyrimidine are reported here. Spherical complex optical potential formalism is used to calculate the positronium formation, elastic, total, and differential cross-sections. The ionization cross-sections calculated here are obtained employing the complex scattering potentialionization contribution method. To account for the complex molecular structure of the target, an effective potential method is employed in our formalism for the first time. The contribution from rotational excitation is also included, which shows a reasonable comparison with the experimental data. The results obtained using the modified approach are encouraging and show very good agreement with the measurements. The differential cross-section for pyridine is reported for the first time.

Pyrimidine (C4H4N2) is considered as the building block of nucleobases, viz., cytosine, thymine and uracil. They provide a blueprint for probing the scattering of radiation by DNA and RNA bases. In this article, we report the elastic and total scattering cross-sections for electron and positron scattering from the pyrimidine molecule, employing a spherical complex optical potential (SCOP) formalism for an extensive energy range of 10 eV to 5 keV. In the case of positron scattering, the original SCOP formalism is modified to adequately solve the positron-target dynamics. Moreover, a reasonable agreement is observed between the present results and other available datasets, for both electron and positron scattering. The cross-sections for electron and positron impact scattering by pyrimidine are necessary input data for codes that seek to simulate radiation damage, and hence are useful to model biomolecular systems.