Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"electron impact ionization"”.
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Electron-impact ionization of molecules
"Electron-impact ionization of molecules has been a fascinating and intriguing subject for decades. For high incident-electron energy ( ̃thousand eV), the collision dynamics has been well described by the plane wave impulse approximation (PWIA) for most molecules. For intermediate and low …
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Electron impact ionization cross sections for carbon vapor.
Massachusetts Institute of Technology. Dept. of Electrical Engineering. Thesis. 1970. Ph.D.
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Accuracy of theory for calculating electron impact ionization of molecules
<p>The study of electron impact single ionization of atoms and molecules has provided valuable information about fundamental collisions. The most detailed information is obtained from triple differential cross sections (TDCS) in which the energy and momentum of all three final state particles are …
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Theoretical calculations for electron impact ionization of atoms and molecules
… has been made for the theoretical treatment of electron impact ionization (e,2e) of atoms and molecules and, for some cases, very nice agreement between experiment and theory has been achieved. In particular, excellent agreement between theory and experiment and theory has been achieved for …
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Computer Calculations of Cross Sections for Electron Impact Ionization of Helium
Triple differential cross sections for electron-impact ionization of helium are calculated in the distorted wave approximation. The distorted wave formalism is discussed for the z-axis parallel to the momentum transfer direction. Problems associated with programming this formalism are outlined. The …
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Miniaturized electron-impact-ionization pumps using double-gated isolated vertically aligned carbon nanotube arrays
… can be readily integrated with other MEMS and electronic components at the chip-scale level. Miniaturized ion pumps exhibit favorable scaling down because they are surface-limited and miniaturization increases the ratio between the active surface and the chamber volume, resulting in enhanced …
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Electron impact excitation-ionization of molecules
… few decades, the study of atomic collisions by electron-impact has made significant advances. The most difficult case to study is electron impact ionization of molecules for which many approximations have to be made and the validity of these approximations can only be checked by comparing with …
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Modeling and Observation of He+ Pickup Ions in the Inner Heliosphere
… the heliosphere. They are produced by photoionization, charge exchange with solar wind ions, and electron impact ionization (EI). Once ionized, they are picked up by the interplanetary magnetic field (IMF) and rapidly swept outward with the solar wind. Typically, pickup ion distributions …
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Internal and External Vibrations of Weakly Bound Molecular Complexes: Infrared Spectroscopy and Vibrational Analysis
… and mass selective detection which employs electron impact ionization and quadrupole mass filtering. A Nd:YAG-pumped optical parametric oscillator (OPO) provided tunable infrared radiation in the 2.5 to 3.5 $\mu$ region.
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Investigation of (E, 2E) Collisions and Related Phenomena
… this thesis I investigate (e, 2e) processes, or electron impact ionization, using several theoretical methods. I first examine the problem using the Born approximations, particularly the Distorted Wave Born Approximation (DWBA), focusing on the underlying processes that dominate for ionization of …
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Comparing water to DNA for simulation of Auger electron direct damage to DNA using Geant4
… interest in targeted tumor therapy using Auger electrons has requires an understand of the radiobological effectiveness of low energy electrons. A chromatin ber was constructed within the Geant4 simulation toolkit down to the molecular level. The Binary Encounter Bethe (BEB) model for electron …
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Double-gated isolated vertically aligned carbon nanofiber field emission and field ionization arrays
Electron impact ionization (ElI) is used extensively in mass spectrometry for gas-phase analytes. Due to the significant amount of fragmentation generated by ElI, the spectrum is usually very noisy. In addition, the thermionic emission electron source used in ElI has a slow response time and …
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Characterization of heat-treated nickel and gold films on silicon single crystals
<p>"An experimental electron impact ionization source was used to determine the presence of various neutral atoms and molecules on metallized and bare surfaces of silicon wafers. The metallization consisted of thin films of nicke l and gold separately and in combination. The major surface …
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Theoretical study of direct and indirect single ionisation by electron impact /
… analyses the processes of single ionisation with electron impact using the distorted wave approximation. The work focuses on W5+, W25+, W26+, Fe3+ and Se3+ ions. The atomic data of these ions are important and have practical application perspectives for understanding and controlling astrophysical …
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Tiesioginės ir netiesioginės viengubos jonizacijos elektronų smūgiais tyrimas /
… analyses the processes of single ionisation with electron impact using the distorted wave approximation. The work focuses on W5+, W25+, W26+, Fe3+ and Se3+ ions. The atomic data of these ions are important and have practical application perspectives for understanding and controlling astrophysical …
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Kinetic processes in a high pressure laser generated plasma
… and the second tuned to either the photoionization threshold of the 3p states near 406 nm or to a higher level 3p-nd resonance. The population densities of the excited levels of atomic sodium were measured with temporal resolution by absolute intensity measurements of excited state …
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A study of micromachined displacement pumps for vacuum generation
… pressure for the ion-pumps to initialize. Field ionization and electron impact ionization pumps that connect to the rough pumps continue to pump from the low vacuum of tens of torr to high vacuum of millitorr or even microtorr. The focus of this thesis work is on the development of the …
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The Concept of Collision Strength and Its Applications
… wide temperature range has been developed for electron impact ionization rates for carbon atoms and ions. The universality of the concept of collision strength is emphasized. This dissertation will show how Arrhenius' chemical reaction rate theory and Thomson's ionization theory can be unified …
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Fast atom bombardment and electron impact mass spectrometry studies of some aryltin compounds and ferrocenes
Both El MS and FAB MS behavior of two groups of compounds, aryltin and ferrocene compounds, have been studied. For the aryltin compounds, the effect of substituent group position, substituent group type and ligand type on the El spectra have been explored in the El MS studies. The fragmentation …
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On the Chemistry of Molecules Containing Silicon, Phosphorus, and Sulfur in the Interstellar Medium
… beamline. In Trento, the ions are generated by electron impact ionization on neutral precursors, while at SOLEIL, they are produced by dissociative photoionization of neutral species, allowing for experiments at a higher energy resolution compared to electron impact. The reactivity has been …
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