Ionization and Electronic State Excitation of CO 2 in Radio-frequency Electric Field
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Ionization and Electronic State Excitation of CO2 in Radio‑frequency Electric Field Violeta V. Stanković1 · Miroslav M. Ristić2 · Mirjana M. Vojnović1 · Muna M. Aoneas3 · Goran B. Poparić1 Received: 22 April 2020 / Accepted: 6 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The rate coefficients for the electron impact ionization and electronic state excitation of the CO2 molecule are calculated in non-equilibrium conditions in the presence of time-dependent electric field. A Monte Carlo simulation has been employed in order to determine nonequilibrium electron energy distribution functions in the C O2 gas, within one period of time-dependent radio-frequency (RF) electric field. By using the distribution functions, ionization rate coefficients for the CO2 molecule have been obtained within one period in RF frequency range at effective reduced electric field up to 500 Td. All obtained rate coefficients have been period averaged, as they can be of use in practical applications in the modeling of RF discharges in CO2. Keywords Carbon dioxide · Electron impact ionization · Electron impact excitation · Rate coefficients · Radio-frequency electric field · Monte carlo simulation · Electron energy distribution functions
Introduction CO2 plasma is a subject of broad interest to different research communities. CO2 dominates in the atmospheres of Mars and Venus; therefore it causes a special attention in astrophysics. The entry of high-speed spacecraft into atmospheres of Mars and Venus, whereby CO2 gas is transformed to the state of plasma, is experimentally simulated by using highfrequency plasma reactors [1, 2]. There is also need to include C O2 in the recently developed atmospheric entry computer models (see for example a recently published article by Annaloro and Bultel [3]). Many investigations are directed to a great number of technological uses. CO2 plasma was found to have advantages over O2 based plasma in low damage * Miroslav M. Ristić [email protected] 1
Faculty of Physics, University of Belgrade, Studentski Trg 12, P.O. Box 44, Belgrade 11000, Serbia
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Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12, P.O. Box 47, Belgrade 11000, Serbia
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University of Zawia, P.O. Box 16418, Zawia, Libya
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Plasma Chemistry and Plasma Processing
photoresist ashing process [4, 5]. CO2 lasers are widely used for material processing, and those using radio-frequency (RF) discharge stand out for their stable beam quality and up to 1 kW output power [6]. In the last few decades the development and use of RF pumped waveguide CO2 lasers has been extensively worked on, due to the high output power produced by this small device [7]. RF generated CO2 lasers have also found some medical applications, such as enamel ablation [8] or treatment of facial scars [9]. Needless to say, the carbon dioxide molecule plays a huge role in climate change. Currently the most important studies for the living world are those aimed at solvi
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