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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...
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Origin of biomolecules over clays under conditions of early terrestrial planets
Hrnčířová, Jana ; Ferus, Martin (advisor) ; Vaculovičová, Markéta (referee)
The mankind has always been interested in the origin of life on Earth or in the universe. The Oparin's theory1 replaced creationist metaphysical theories (of gods' actions on Earth to create life) in the beginning of the twentieth century. This theory explained production of basic building blocks of life like amino acids, nucleobases and sugars from abiogenic mixture of gases and subsequent formation of so-called coacervates. The synthesis of amino acids was then confirmed by experiments of Miller and Urey2 . Especially the theory of simple formation of nucleobases became an essential contradiction between evolutionary and molecular biologists and chemists. From biological point of view it seems very probable that primal life structures were based on the self-replicating molecule of RNA. From chemical point of view the synthesis of nucleobases seemed very problematic, therefore the models of life structures based on amino acids were favorited. This opposes the basic dogma of molecular biology, which postulates one-way transcriptions of nucleobases' sequence into amino acids' sequence exclusively. In our experiments we follow the idea of simple production of nucleobases from formamide molecule in possible primordial conditions. The mixture of formamide with different types of clays was exposed to...
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Laboratory astrochemistry and applications of computer simulations
Roučka, Štěpán ; Hrach, Rudolf (advisor) ; Bonaventura, Zdeněk (referee) ; Novák, Stanislav (referee)
This work is focused on laboratory studies of ion chemistry at conditions relevant for astrophysics. The three main outcomes of the thesis are: (1) The experimental study of the reaction rate coefficient of the associative detachment reaction H- + H -> H2 + e-; measurement of the thermal rate coefficient at the temperatures in the range 10-135 K is described. (2) The design of a novel apparatus for detecting the electrons produced in the RF trap and measuring their energy; numerical simulations and preliminary experimental results are presented. (3) The development of a model of the electron cooling in the afterglow plasma and the application of the model in the analysis of the H3+ recombination measurements.
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Water formation in reactions of anions and/or cations with molecular hydrogen at low temperature
Tran, Thuy Dung ; Plašil, Radek (advisor)
In the present work, the results of the experimental study of reactions of ions with molecular hydrogen in the temperature range 15 - 300 K using a 22-pole ion trap apparatus are presented. The reaction of OD- with para-enriched hydrogen was studied using a combination of the 22-pole ion trap apparatus with a para-hydrogen generator. Also reactions of O- with H2, D2, and HD were studied. These reactions have a channel of water production and a channel of hydrogen or deuterium transfer. Another field of study was a sequence of reactions of oxygen hydride cations with H2 and D2 which leads to the production of H3O+ or its isotopic variant, specifically reactions OH+ with H2, H2O+ with H2, D2O+ with H2, and D2O+ with D2. This reaction chain can be followed by the electron recombination of H3O+ or its isotopologue, which has a channel of water production.
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Water formation in reactions of anions and/or cations with molecular hydrogen at low temperature
Tran, Thuy Dung ; Plašil, Radek (advisor)
In the present work, the results of the experimental study of reactions of ions with molecular hydrogen in the temperature range 15 - 300 K using a 22-pole ion trap apparatus are presented. The reaction of OD- with para-enriched hydrogen was studied using a combination of the 22-pole ion trap apparatus with a para-hydrogen generator. Also reactions of O- with H2, D2, and HD were studied. These reactions have a channel of water production and a channel of hydrogen or deuterium transfer. Another field of study was a sequence of reactions of oxygen hydride cations with H2 and D2 which leads to the production of H3O+ or its isotopic variant, specifically reactions OH+ with H2, H2O+ with H2, D2O+ with H2, and D2O+ with D2. This reaction chain can be followed by the electron recombination of H3O+ or its isotopologue, which has a channel of water production.
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Water formation in reactions of anions and/or cations with molecular hydrogen at low temperature
Tran, Thuy Dung ; Plašil, Radek (advisor) ; Španěl, Patrik (referee) ; Rubovič, Peter (referee)
In the present work, the results of the experimental study of reactions of ions with molecular hydrogen in the temperature range 15 - 300 K using a 22-pole ion trap apparatus are presented. The reaction of OD- with para-enriched hydrogen was studied using a combination of the 22-pole ion trap apparatus with a para-hydrogen generator. Also reactions of O- with H2, D2, and HD were studied. These reactions have a channel of water production and a channel of hydrogen or deuterium transfer. Another field of study was a sequence of reactions of oxygen hydride cations with H2 and D2 which leads to the production of H3O+ or its isotopic variant, specifically reactions OH+ with H2, H2O+ with H2, D2O+ with H2, and D2O+ with D2. This reaction chain can be followed by the electron recombination of H3O+ or its isotopologue, which has a channel of water production.
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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...
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Origin of biomolecules over clays under conditions of early terrestrial planets
Hrnčířová, Jana ; Ferus, Martin (advisor) ; Vaculovičová, Markéta (referee)
The mankind has always been interested in the origin of life on Earth or in the universe. The Oparin's theory1 replaced creationist metaphysical theories (of gods' actions on Earth to create life) in the beginning of the twentieth century. This theory explained production of basic building blocks of life like amino acids, nucleobases and sugars from abiogenic mixture of gases and subsequent formation of so-called coacervates. The synthesis of amino acids was then confirmed by experiments of Miller and Urey2 . Especially the theory of simple formation of nucleobases became an essential contradiction between evolutionary and molecular biologists and chemists. From biological point of view it seems very probable that primal life structures were based on the self-replicating molecule of RNA. From chemical point of view the synthesis of nucleobases seemed very problematic, therefore the models of life structures based on amino acids were favorited. This opposes the basic dogma of molecular biology, which postulates one-way transcriptions of nucleobases' sequence into amino acids' sequence exclusively. In our experiments we follow the idea of simple production of nucleobases from formamide molecule in possible primordial conditions. The mixture of formamide with different types of clays was exposed to...
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Experimental study of chemical evolution of biomolecules under early Earth conditions
Knížek, Antonín ; Ferus, Martin (advisor) ; Adam, Vojtěch (referee)
Origin of life is a still-enduring gap in human knowledge. This work is focused on revealing of several pieces of this puzzle. State of the art scenarios of biomolecules synthesis under prebiotic conditions are presented and discussed. This thesis presents our recent experiments suggesting a novel idea that neutral planetary atmosphere containing a mixture of neutral volcanic-type gasses (CO2, N2, H2O) can be converted over acidic mineral catalysts upon irradiation by a soft UV-radiation into a relatively reactive mixture of reducing gases (CH4, CO), which can be further reprocessed by high-energy chemistry. The resulting mixture (CH4, CO + N2) represents a common reducing atmosphere related e.g. to the chemistry of Titan, the largest moon of Saturn, as well as a possible representation of the secondary atmosphere of our planet. Also, photocatalytic reduction of CO2-rich atmosphere can explain the abiotic origin of methane on current Mars or other terrestrial planets. In our subsequent experiments, corresponding equimolar model mixture of CH4 : CO : N2 in presence of water vapour was subjected to reprocessing by high-power laser plasma simulating an asteroid impact - one of a series of impact events which the young Earth experienced during the first 600 million years of her history. Upon delivery...
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Negative Ion Astrochemistry - a Laboratory Study
Jusko, Pavol ; Glosík, Juraj (advisor) ; Fárník, Michal (referee) ; Korolov, Ihor (referee)
A B S T R A C T Presented work focuses on experimental study of anion interaction with neutral particles at temperatures relevant for astrophysics. Anion H− , important for molecular hydrogen creation, and O− as a possible source of water are investigated. The temperature dependence of reac- tion rate coefficients from 10 to 150 K for reactions H− + H → H2 + e− and O− + H2 → H2O + e− has been determined. The energy distri- bution of electrons produced in the latter reaction at 300 K has also been acquired. These studies have been performed on two experimen- tal setups, which are presented together with the theory of operation, construction details, calibration, and supporting test measurements.
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