Citation: Khandker, M.H.; Khatun, M.M.; Billah, M.M.; Haque, M.M.; Watabe, H.; Haque, A.K.F.; Uddin, M.A. Scattering of e ± from CF 3 I Molecule. Atoms 2022, 10, 85. https://doi.org/10.3390/ atoms10030085 Academic Editor: Grzegorz Piotr Karwasz Received: 31 July 2022 Accepted: 20 August 2022 Published: 24 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). atoms Article Scattering of e ± from CF 3 I Molecule Mahmudul H. Khandker 1 , M. Mousumi Khatun 1,2 , M. Masum Billah 1 , M. M. Haque 1 , Hiroshi Watabe 3 , A. K. Fazlul Haque 1,3, * and M. Alfaz Uddin 1 1 Atomic and Molecular Physics Research Laboratory, Department of Physics, University of Rajshahi, Rajshahi 6205, Bangladesh 2 Institute of Fuel Research and Development (IFRD), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhanmondi, Dhaka 1205, Bangladesh 3 Division of Radiation Protection and Safety Control, Cyclotron and Radioisotope Center, Tohoku University, 6-3 Aoba, Aramaki, Aoba, Sendai 980-8578, Japan * Correspondence: fhaque@ru.ac.bd; Tel.: +880-721-711102 Abstract: Theoretical investigation of the scattering of electrons and positrons from the plasma etching gas trifluoroiodomethane (CF 3 I) is presented in the present work. The investigation is carried out by taking into account the screening correction arising from a semiclassical analysis of atomic geometrical overlapping of the scattering cross-sections calculated in the independent atom approximation. The scattering system e ± -CF 3 I is studied through the calculations of the observable quantities, namely, absolute differential, Sherman function, total elastic and inelastic, momentum transfer, viscosity, ionization and total cross sections over the energy range 1 eV–1 MeV. Energy dependency of the differential cross section and Sherman function are also picturized in this work. A comparative study is carried out between scattering observables for electron impact with those for positron impact to get a better understanding of the interaction and dynamics of the collision process. The corresponding scattering quantities of the constituent atoms are calculated employing a complex optical model potential by solving the Dirac relativistic wave equations in the framework of partial wave analysis. The comparison of our results with the available experimental and theoretical data shows a reasonable agreement. Keywords: electron and positron scattering; molecular scattering; CF 3 I; independent atom model; screening correction 1. Introduction The knowledge of electron–molecule (or atom) collision plays a significant role in understanding the structure of atoms and molecules, the interaction of ionizing radiation with matter, the deposition of energy by radiation in matter, the interactions and transport of electrons in plasmas, and the behavior of electrons in the condensed phases of matter [1]. This fundamental knowledge is of practical importance in many research and technological areas such as magneto-hydrodynamic power generation, material processing applications, manufacturing semiconductor devices, plasma-assisted combustion, modeling of various laser systems, electron beam technology, radiology and dosimetry, mass spectrometry, atmospheric physics, astrophysics, astrochemistry, applied atomic physics, photochemistry, auroras, supernova ejecta, artificial, terrestrial, space and astrophysical plasmas, etc. [2–5]. On the other hand, a comprehensive data set of positron impact molecular scattering cross- sections is required in astrophysical research, radiation-based technologies, and energy deposition models [6]. In addition to general importance, CF 3 I carries special attention, as a promising feedstock gas, in the semiconductor plasma industry. Perfluorocarbons, the main feed gases used in the plasma processing industry, are strong greenhouse gases due to their large infrared absorption and long atmospheric lifetime. These environmental reasons have led to an international agreement (under the Kyoto protocol) to phase out the use of Atoms 2022, 10, 85. https://doi.org/10.3390/atoms10030085 https://www.mdpi.com/journal/atoms