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  • electron velocity distribution function  (6)
  • Organic Chemistry  (5)
  • Boltzmann equation  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Impact of electron-electron interaction on the electron energy distribution function in molecular plasmas under rf field action (1992)
    Springer
    Plasma chemistry and plasma processing 12 (1992), S. 71-87 
    Details
    ISSN: 1572-8986
    Keywords: Electron-electron interaction in rf plasmas ; CO ; H2 ; Boltzmann equation ; electron energy distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Calculations of the electron energy distribution and of relevant macroscopic quantities of collision-dominated, weakly ionized plasmas under rf field action have been performed with increasing degrees of ionization, and the impact of the electron-electron interaction on these quantities was determined. The investigations were performed for the gas plasmas in CO and H2 as representatives of molecular plasmas The energy distribution and macroscopic quantities are obtained by solving the nonstationary Bolizmann equation for a given rf field and degree of ionization taking into accoung and additional Fokker-Planck term besides the collision integrals for the elastic and the main inelastic collision processes. In these molecular plasmas a remarkable impact of the electron-electron interaction connected with increasing Maxwellization is observed for degrees of ionization greater than 10.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447945
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  • 2
    Electronic Resource
    Electronic Resource
    Attachment and ionization in a self-consistent treatment of the electron kinetics of a collision-dominated rf plasma (1987)
    Springer
    Plasma chemistry and plasma processing 7 (1987), S. 245-265 
    Details
    ISSN: 1572-8986
    Keywords: rf plasma ; electron kinetics ; Boltzmann equation ; electron energy distribution function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract This paper deals with the self-consistent determination of the rf field amplitude for sustaining the steady-state collision-dominated weakley ionized plasmas in the bulk of the rf discharge and of the time-resolved behavior of the isotropic part of the distribution function as well as of relevant macroscopic quantities in plasmas whose particle loss is dominantly determined by electron attachment. The strict timeresolved treatment is based on the nonstationary Boltzmann equation of the electrons and its numerical solution including, apart from electron number conservative collision processes, the electron attachment and ionization. The investigations are related to an rf plasma in a model gas and in SF6 and are performed for reduced rf field frequencies around 10 MHz Torr−1 which are of particular interest from the point of application of rf discharges for plasma processing. The numerical results show that a large field amplitude of around 160 V cm−1 Torr−1 is necessary to maintain the discharge and that the isotropic distribution, the relevant collision frequencies for attachment and ionization, and the electron density undergo a large modulation during a period of the rf field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01016516
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  • 3
    Electronic Resource
    Electronic Resource
    Two-Term and multi-term approximation of the nonstationary electron velocity distribution in an electric field in a gas (1996)
    Springer
    Plasma chemistry and plasma processing 16 (1996), S. 287-300 
    Details
    ISSN: 1572-8986
    Keywords: Nonstationary Boltzmann equation ; electron velocity distribution function ; multi-term approximation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract A very efficient, strict nonstationary multi-term approach has been developed as a generalization of the conventional and the strict nonstationary two-term approximations used for solving the nonstationary , electron Boltzmann equation. As a first application the temporal relaxation of electrons in a model plasma acted upon by a de electric field has been investigated. The results are compared with corresponding ones obtained by the conventional and the strict nonstationary two-term approach as well as with very accurate Monte Carlo simulations. Perfect agreement between nonstationary eight-term Boltzmann and Monte Carlo calculations is found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447147
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  • 4
    Electronic Resource
    Electronic Resource
    Radial structure of the kinetics and production of electrons in the dc column plasma (1996)
    Springer
    Plasma chemistry and plasma processing 16 (1996), S. 517-545 
    Details
    ISSN: 1572-8986
    Keywords: Spatially inhomogeneous Boltzmann equation ; electron velocity distribution function ; positive column ; dc glow discharge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The detailed radial structure of the electron kinetics in the positive column of cylindrical dc glow discharges is investigated to reveal the microscopic nature of the electron confinement by the radial space charge potential and the spatial dependences of the macroscopic electron quantities. Therefore, in order to determine the radial variation of the isotropic and anisotropic parts of the electron velocity distribution function the relevant inhomogeneous kinetic equation is solved taking into account the radial electric field action. The kinetic description includes the self-consistent calculation of the excited gas atom densities by solving their radially inhomogeneous particle balance equations. This permits one to determine accurately the electron production in the volume which is ollen dominated by ionization of excited atoms. Besides the main aspects of the numerical approach, results for a neon and krypton glow discharge are presented. The discussion includes a detailed analysis of the local electron energy balance equation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447007
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  • 5
    Electronic Resource
    Electronic Resource
    On the Nonlocal Electron Kinetics in s- and p-Striations of DC Glow Discharge Plasmas: I. Electron Establishment in Striation-like Fields (1998)
    Springer
    Plasma chemistry and plasma processing 18 (1998), S. 153-180 
    Details
    ISSN: 1572-8986
    Keywords: s- and p-Striations ; spatially inhomogeneous Boltzmann equation ; electron velocity distribution function ; dc glow discharge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The nonlocal behavior of the electrons in strongly modulated and period-averaged electric fields typical of s- and p-striations in neon glow discharge plasmas is investigated by numerically solving the axially inhomogeneous electron Boltzmann equation. A good agreement between the period lengths measured in the striations and those obtained from the spatially periodic electron relaxation in the period-averaged field of the striations is found confirming the close relation of both phenomena. The s- and p-striations represent the fundamental and first harmonics of the inherent periodic electron relaxation. Furthermore, starting from different boundary conditions the establishment of the velocity distribution function and of selected macroscopic quantities of the electrons into unique periodic states under the action of strongly modulated striation-like fields is investigated. It is shown that the same damping processes that cause in homogeneous fields a relaxation into homogeneous states lead to unique periodic states in strongly modulated fields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021694231064
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  • 6
    Electronic Resource
    Electronic Resource
    A New Method of the Microwave Diagnostics for Determining the Electron Density (1999)
    Springer
    Plasma chemistry and plasma processing 19 (1999), S. 111-130 
    Details
    ISSN: 1572-8986
    Keywords: dc glow discharge ; microwave measurements ; electron density determination by microwaves ; microwave resonator method ; high-frequency electron current ; electron velocity distribution function ; time-dependent Boltzmann equation ; temporal electron relaxation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract A improved method of the microwave diagnostics for the determination of the electron density in the column plasma of dc glow discharges is presented. This method overcomes significant limitations involved in the conventional method. The latter is mainly based on the measurement of the resonance frequency shift of the resonator cavity caused by the presence of the dc column plasma and is strictly valid only in the so-called high field frequency limit of the resonator operation. Of significant importance with respect to the improved method is the additional inclusion of the measurable phase delay between the electric hf field, superimposed on the dc plasma by the microwave field of the resonator, and the induced hf electron current. This new method has been critically evaluated with respect to its extended applicability and has been successfully applied to the experimental determination of the electron density in dc plasmas of neon and molecular nitrogen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021860117474
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  • 7
    Electronic Resource
    Electronic Resource
    Kinetics of the Electrons in Striations of Spherical Glow Discharges (2000)
    Springer
    Plasma chemistry and plasma processing 20 (2000), S. 87-110 
    Details
    ISSN: 1572-8986
    Keywords: striations ; nitrogen ; spherical discharge ; spatially inhomogeneous Boltzmann equation ; electron velocity distribution function ; dc glow discharge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Recent observations of spherical striations in large-volume nitrogen dcdischarges with a central anode have stimulated investigations of thenonlocal electron kinetics in these striations by solving the spatiallyinhomogeneous Boltzmann equation adapted to spherical geometry. Becausethe radial course of the electric potential is largely unknown in thisdischarge, different models concerning its radial course have been developedand used. These models are based on the measured radii of the striationsand the assumption that the potential drop between successive striationsdoes not change. As a consequence, with decreasing distance between thestriations the electric field strongly increases toward the centralanode. It has been found that spherical striations are only obtained ifthe electric field is strongly modulated. In this case, a highly nonlocalbehavior of the velocity distribution function and strongly modulatedradial courses of the macroscopic quantities have been obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006973911319
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  • 8
    Electronic Resource
    Electronic Resource
    Microwave Diagnostics in Diffusive and Constricted Medium-Pressure Discharges (2000)
    Springer
    Plasma chemistry and plasma processing 20 (2000), S. 111-135 
    Details
    ISSN: 1572-8986
    Keywords: dc glow discharge ; microwave measurements ; electron density determination by microwaves ; microwave resonator method ; high-frequency electron current ; electron velocity distribution function ; time-dependent Boltzmann equation ; temporal electron relaxation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The high-frequency (HF) electron current induced in a dc discharge plasma bysuperimposing a HF electric field presents a useful tool for the diagnosticsof the time-dependent electron behavior of the plasma. This response to theHF field has been recently studied in diffusive discharge plasmas at lowergas pressures and discharge currents. These studies are extended tomedium-pressure plasmas operating in the diffusive as well as in theconstricted mode. In particular, the impact of the electron–electroninteraction on the phase delay between the HF field and electron current inconstricted column plasmas has been experimentally and theoreticallyanalyzed. Furthermore, the problem has been studied if, under the conditionsof pronounced electron–electron interaction, the determination of theelectron density will further on be possible by using the phase delay. Themeasurements of the delay have been performed by means of the microwaveresonator method in a medium-pressure krypton glow discharge operating inthe diffusive as well as the strongly constricted mode. In addition, thedelay has been theoretically determined by treating the appropriatetime-dependent electron kinetic equation at high frequencies of thesuperimposed microwave field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006926028157
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  • 9
    Electronic Resource
    Electronic Resource
    Studien zur Chemie der Paraffine und Paraffingatsche. V. Synthese und physikalische Eigenschaften einiger 4n-Propyl- und 2-Methyl-3-isopropyl-Alkane mit mehr als 10 C-Atomen (1959)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 9 (1959), S. 275-288 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es werden die wichtigsten Synthesen verzweigtkettiger Alkane hinsichtlich Ausbeute und Reinheit der Endprodukte diskutiert. Am geeignetsten wurde für die Synthese der 4n-propyl- und 2-Methyl-3-isopropyl-Alkane die GRIGNARD-Reaktion gefunden.Von den dargestellten verzweigtkettigen Alkanen wurden Dichte, Brechungsindex, Oberflächenspannung, Kochpunkt, % C und % H bestimmt, Molvolumen, Molrefraktion und Parachor berechnet. Weiterhin wurden IR-Spektrogramme aufgenommen und die Fähigkeit der Adduktbildung mit Harnstoff untersucht.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19590090508
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  • 10
    Electronic Resource
    Electronic Resource
    Zur Konstitution von Demecolcin (Substanz F) aus Colchicum autumnale L. Substanzen der Herbstzeitlose und ihre Derivate 35. Mitteilung (1953)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 36 (1953), S. 1319-1324 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Als neue Bezeichnung für die Substanz F aus Herbstzeitlosen wird der Trivialname Demecolcin vorgeschlagen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19530360613
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