National Repository of Grey Literature 5 records found  Search took 0.01 seconds. 
Elementary Processes at Low Temperatures - Reactions of H3+ and N2H+ in Afterglow Plasmas
Kálosi, Ábel ; Plašil, Radek (advisor) ; Rubovič, Peter (referee) ; Španěl, Patrik (referee)
Electron-ion recombination and ion-neutral interactions play a piv- otal role in the chemical evolution of molecules in the Interstellar Medium (ISM). Physical conditions under which these processes un- dergo in the ISM include a wide range of temperatures and particle number densities. This work contributes to the experimental study of named low temperature phenomena in the range of 30 K to 300 K focusing on the reactions of hydrogen-containing light molecules. The employed experimental techniques are based on a combination of a Stationary Afterglow (SA) instrument with a Continuous Wave Cavity Ring-down Spectrometer (cw-CRDS). The main contributions of this work can be split into three topics. (1) The proton and deuteron con- taining isotopic system of H3 + ions. The isotopic fractionation process in collisions with hydrogen and deuterium gas was investigated in low temperature discharges, nominal ion temperatures of 80 K to 140 K, to deduce relative ion densities in the experiments. These are necessary for afterglow studies of isotopic effects in electron-ion recombination of the studied ions. (2) Vibrational spectroscopy of N2H+ ions focusing on first overtone (2ν1 band) transitions and ion thermometry, the first step towards studies of electron-ion recombination. (3) The role of para/ortho spin...
Recombination of ions in plasma at 50-300 K
Rubovič, Peter
A B S T R A C T Title: Recombination of Ions in Plasma at 50 − 300 K Author: Peter Rubovič Supervisor: Prof. RNDr. Juraj Glosík, DrSc. Abstract: Main part of this doctoral thesis lies in a study of recom- bination of atomic and molecular ions in low temperature plasmatic environment with emphasis on effect of third bodies. Stationary After- glow equipped with Cavity Ring Down Spectrometer and Cryogenic Flowing Afterglow with Langmuir Probe II were used to obtain recom- bination rate coefficients. Electron assisted collisional radiative recom- bination of Ar+ ion was studied in the temperature range of 50−100 K and helium assisted collisional radiative recombination was observed too. Both H+ 3 and its isotopologue D+ 3 were studies in flowing after- glow and spectroscopically in stationary afterglow as well. Binary re- combination rate coefficients and ternary recombination rate coeffi- cients for helium assisted ternary recombination were determined in the temperature range of 50 − 250 K. These coefficients were deter- mined also for pure ortho- and para- nuclear spin configurations of H+ 3 in the temperature range of 80 − 200 K. Keywords: dissociative recombination, collisional radiative recombi- nation, H+ 3 , D+ 3 , Ar+ viii
Recombination of ions in plasma at 50-300 K
Rubovič, Peter ; Glosík, Juraj (advisor) ; Fárník, Michal (referee) ; Korolov, Ihor (referee)
A B S T R A C T Title: Recombination of Ions in Plasma at 50 − 300 K Author: Peter Rubovič Supervisor: Prof. RNDr. Juraj Glosík, DrSc. Abstract: Main part of this doctoral thesis lies in a study of recom- bination of atomic and molecular ions in low temperature plasmatic environment with emphasis on effect of third bodies. Stationary After- glow equipped with Cavity Ring Down Spectrometer and Cryogenic Flowing Afterglow with Langmuir Probe II were used to obtain recom- bination rate coefficients. Electron assisted collisional radiative recom- bination of Ar+ ion was studied in the temperature range of 50−100 K and helium assisted collisional radiative recombination was observed too. Both H+ 3 and its isotopologue D+ 3 were studies in flowing after- glow and spectroscopically in stationary afterglow as well. Binary re- combination rate coefficients and ternary recombination rate coeffi- cients for helium assisted ternary recombination were determined in the temperature range of 50 − 250 K. These coefficients were deter- mined also for pure ortho- and para- nuclear spin configurations of H+ 3 in the temperature range of 80 − 200 K. Keywords: dissociative recombination, collisional radiative recombi- nation, H+ 3 , D+ 3 , Ar+ viii
Plasma-jet systems - experiment and model
Rubovič, Peter ; Hubička, Zdeněk (referee) ; Kudrna, Pavel (advisor)
In the present work we study the ow of working gas through a plasmajet system. In this work we describe the basic principle of hollow cathode discharge and its use for technological applications, mainly for thin layers coating. One of the important parameters during the deposition is the speed of the working gas ow and with it the sputtered target material towards the substrate. Because of the reproducibility and precision of the experiments it is important to know the relation between the working gas ow and external parameters of the experiment, e.g. ow of the gas and the pressure in the chamber. This is the reason why measurements of ions velocity using Langmuire electrostatic probe and pulse regime of plasmajet were done. Measured data are compared with a computer model, which was developed in this work. This model describes the ow of the working gas by solving Navier-Stokes equation for compressible Newtonian uids. The results of this model are compared with results from the paper describing the ow through the hollow cathode. It shows good agreement inside the cathode. The model is giving dierent results when comparing to measured data which are from the area outside the cathode. Part of the model description is a discussion of the temperature dependence of the ow.

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