DOCSLIB.ORG

Reaction Chemistry in Oxygen Or Hexamethyldisiloxane Containing Noble Gas Microplasma Jets : a Quantitative Molecular Beam Mass

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Reaction Chemistry in Oxygen Or Hexamethyldisiloxane Containing Noble Gas Microplasma Jets : a Quantitative Molecular Beam Mass Reaction chemistry in oxygen or hexamethyldisiloxane containing noble gas microplasma jets: a quantitative molecular beam mass spectrometry study Dissertation zur Erlangung des Grades „Doktor der Naturwissenschaften“ an der Fakultät für Physik und Astronomie der Ruhr-Universität Bochum von Dirk Ellerweg aus Troisdorf Bochum 2012 1. Gutachter: Prof. Dr. Achim von Keudell 2. Gutachter: Prof. Dr. Peter Awakowicz Datum der Einreichung: 11. November 2011 Datum der Disputation: 02. Februar 2012 Contents 1 Introduction and Motivation 5 2 Fundamentals 9 2.1 Microplasma . 9 2.1.1 Applications . 12 2.1.1.1 Biomedical applications . 12 2.1.1.2 Deposition of silicon dioxide film . 13 2.2 Mass spectrometry for microplasma diagnostics . 16 2.2.1 Threshold ionization mass spectrometry . 23 2.2.2 Calibration of a mass spectrometer . 24 2.2.3 Molecular beam mass spectrometry . 25 2.2.4 Molecular beam . 28 2.2.5 Composition distortion . 32 2.3 Laser induced fluorescence spectroscopy . 35 2.4 Comparison between MBMS and TALIF . 36 3 Experiment 37 3.1 Atmospheric pressure microplasma jet . 37 3.2 X-Jet . 39 3.3 Molecular beam mass spectrometer . 39 4 Fluid model of the plasma euent 47 4.1 Model of the gas flow . 47 4.2 Model of chemical kinetics . 49 5 Results 53 5.1 Performance of the molecular beam mass spectrometer . 53 5.1.1 Influence of the chopper design on the signal . 53 5.1.2 Analysis of air . 59 5.1.3 Mass dependence of the peak shape . 61 5.1.4 Gas flow rate into the MBMS system . 62 5.2 Calibration of the MBMS system . 63 3 Contents 5.3 Production of reactive oxygen species . 68 5.3.1 Measurement of neutral species . 68 5.3.2 Effluent chemistry in ambient air . 74 5.3.3 Measurement of ions . 82 5.4 Analysis of hexamethyldisiloxane containing microplasmas . 90 5.4.1 Measurement of positive ions . 90 5.4.2 Measurement of neutral species . 93 6 Conclusion and Outlook 107 Bibliography 111 4 1 Introduction and Motivation Cold atmospheric plasmas exhibit many unique properties, which make them highly attractive for a broad field of applications. This kind of plasma combines the advan- tages of low pressure and atmospheric pressure plasmas without their respective dis- advantages. Low pressure plasmas are low temperature, non-equilibrium plasmas. They are used commonly in industry for e.g. thin film deposition or etching especially in semicon- ductor industries. However, a complicated vacuum system is needed to sustain the plasma. Atmospheric pressure plasmas, on the contrary, are operated at atmospheric pressure with no need for a vacuum system. These plasmas are used for several ap- plications like ozone generation, activation and cleaning of surfaces in the case of cold non-equilibrium plasmas or plasma spraying and plasma welding in the case of hot thermal plasmas. The key advantage of atmospheric pressure plasmas is that they can be easily integrated in existing production lines. However, they tend to form thermal arcs and filaments, which restricts the field of applications. Overall, cold atmospheric plasmas offer non-equilibrium chemistry at atmospheric pressure with high densities of reactive neutral and charged species and high fluxes of photons. Especially, treatment of temperature and vacuum sensitive materials is made possible. Prominent applications are e.g. treatment of polymers or living tis- sues and localized deposition of thin films. However, considerable differences exist between cold atmospheric plasmas and low pressure plasmas. The short mean free path and the high collision rate due to the high pressure have a high impact on the plasma chemistry. Therefore, the plasma chemistry at atmospheric pressure is, in contrast to low pressure plasmas, only poorly understood. This work focuses on microplasma jets, a special kind of cold atmospheric plasmas with a high gas flow through a micro-scaled discharge. The reactive species generated in the micro discharge are delivered by the gas flow to a surface to be treated. In re- cent years, many different sources have been developed and studied for a variety of applications. A promising field of applications of microplasma jets that has to be highlighted is the relatively new field of plasma medicine. It has been observed that pathogens are 5 1 Introduction and Motivation deactivated under plasma exposure. Consequently, microplasma jets can be used for a localized treatment of living tissue and wounds to accelerate wound healing. How- ever, since plasmas are complex systems consisting of electrons, ions, reactive species, and photons, it is challenging to reveal the precise bacteria deactivation mechanism. Reactive species, like atomic oxygen and ozone, are supposed to play a crucial role during the inactivation of bacteria. A synergism between the different plasma con- stituents is also likely. The measurement of absolute densities of reactive species generated by a microplasma jet are of high interest in the study of these reaction mechanisms. However, it is a chal- lenging task due to the high pressure and the small dimensions of the jet. Many of the standard diagnostics of low pressure plasma cannot be applied. A specially designed molecular beam mass spectrometer has therefore been developed within the scope of this work. This mass spectrometer is perfectly suited for analysis of atmospheric pressure plasmas due to its very high sensitivity. In this thesis, the production of reactive oxygen species in a helium/oxygen micro- plasma jet is studied in detail by molecular beam mass spectrometry. The questions of particularly interest are: • What are the optimal conditions for generation of atomic oxygen and ozone? • How do these densities behave with increasing distance from the nozzle of the plasma jet? For reasons of simplicity, all prospective microplasma jet applications take place in air ambiance. The effect of admixing air into the effluent may severely affect the compo- sition of the emerging species. The questions, which are to be solved are: • How much air does admix into the effluent of the microplasma jet? • Does the air admixture has a big influence on the atomic oxygen and ozone densities? • Which are the important reactions in the effluent and does UV radiation play a crucial role? Especially the last question can be solved by comparing the measured densities to results of a fluid model of the plasma effluent. The developed molecular beam mass spectrometer is also capable to measure positive and negative ions. • However, are ions still left in the effluent of the plasma jet? • If so, how are they produced? The gained knowledge can be used to optimize the process of surface treatment and, especially, bacteria deactivation. 6 Plasmas are also widely used for deposition of surface coatings, for example SiO2-like films of good quality are desired in industry. Over the past years, the research fo- cused on deposition of silicon oxide films at atmospheric pressure to achieve as good films as in low pressure plasmas. However, the studies are often limited to an analysis of the resulting silicon oxide film, such as measurements of the deposition rate and the elemental composition of the film. For a precise comprehension of the deposition mechanism of silicon oxide films, the plasma itself must be analyzed. A He/O2 microplasma jet with admixtures of hexamethyldisiloxane is used in combi- nation with the molecular beam mass spectrometer to study the microplasma chem- istry leading to depositions of SiO2-like films. The questions of particularly interest are: • Under which conditions is the hexamethyldisiloxane consumption maximized and how large is the consumption? • Which reaction products are generated in the hexamethyldisiloxane plasma and what are their absolute densities? • Do ions contribute to the film growth at atmospheric pressure? The answers to these questions can contribute to a more precise understanding of the deposition mechanism at atmospheric pressure. Outline of the thesis The following chapter provides the necessary background knowledge regarding mi- croplasmas, their applications, and the diagnostics used. The principle of mass spec- trometry, and particularly molecular beam mass spectrometry and composition dis- tortion are explained here in detail. Chapter three introduces the experimental setup used in this work. The different ver- sions of the microplasma jet and the design of the molecular beam mass spectrometer are described here. A fluid model of the plasma effluent is defined in the next chapter. The fluid model has been developed for a better understanding of the reaction chemistry going on in the effluent. The results of the measurements are presented and discussed in chapter five. First, the performance of the molecular beam mass spectrometer is demonstrated by means of several test measurements and the calibration procedure is explained. Then the measurements of oxygen and hexamethyldisiloxane microplasma jets are shown. The measurements of reactive oxygen species in the effluent are also compared to the re- sults of the fluid model. The final chapter summarizes the thesis and gives a brief outlook on prospective in- vestigations. 7 2 Fundamentals In this thesis, the plasma chemistry of a microplasma jet has been analyzed by means of mass spectrometry. The necessary fundamentals are provided in this chapter. First, an introduction into microplasmas is given. Their possible applications are explained in detail with the help of two examples, which are of particular interest for this work. The following section focuses on the principle of mass spectrometry. For the analy- sis of atmospheric pressure plasmas, molecular beam mass spectrometry needs to be applied and, therefore, is explained here. When absolute densities should be deter- mined, one needs to understand the behavior of a molecular beam and its influence on the initial gas composition. These informations are provided here. The principle of two-photon absorption laser induced fluorescence spectroscopy is described as well. 2.1 Microplasma »Except near the electrodes, where there are sheaths containing very few electrons, the ionized gas contains ions and electrons in about equal num- bers so that the resultant space charge is very small.
Load more

Recommended publications
  • Conformations of Cyclopentasilane Stereoisomers Control Molecular Junction Conductance
    Electronic Supplementary Material (ESI) for Chemical Science. This journal is © The Royal Society of Chemistry 2017 Supporting Information Conformations of Cyclopentasilane Stereoisomers Control Molecular Junction Conductance Haixing Li,1 Marc H. Garner,2 Zhichun Shangguan,3 Timothy A. Su,4 Madhav Neupane,4 Panpan Li,3 Alexandra Velian,4 Michael L. Steigerwald,4 Shengxiong Xiao,*3 Colin Nuckolls,*3,4 Gemma C. Solomon,*2 Latha Venkataraman*1,4 1 Department of Applied Physics and Applied Mathematics, Columbia University, New York 10027, USA 2 Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark 3 The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China 4 Department of Chemistry, Columbia University, New York 10027 This version of the ESI replaces the previous version that was published on 13th June 2016. Some references in Part IV on Page 8 and 21 are corrected and updated. 1 Table of Contents Table of Contents .............................................................................................. 2 I. Synthetic procedures and characterization of compounds ......................... 4 II. STM-Break Junction experiment details ..................................................... 6 III. Additional Data .........................................................................................
    [Show full text]
  • Chlorotrimethylsilane
    Chlorotrimethylsilane Health-based recommended occupational exposure limit Gezondheidsraad Voorzitter Health Council of the Netherlands Aan de Staatssecretaris van Sociale Zaken en Werkgelegenheid Onderwerp : Aanbieding adviezen over Chloortrimethylsilaan en Butylacetaten Uw kenmerk : DGV/MBO/U-932542 Ons kenmerk : U 2173/AvdB/tvdk/459-D35 Bijlagen : 2 Datum : 15 november 2001 Mijnheer de Staatssecretaris, Bij brief van 3 december 1993, nr. DGV/BMO-U-932542, verzocht de Staatssecretaris van Welzijn, Volksgezondheid en Cultuur namens de Minister van Sociale Zaken en Werkgelegenheid om gezondheidskundige advieswaarden af te leiden ten behoeve van de bescherming van beroepsmatig aan stoffen blootgestelde personen. Per 1 januari 1994 heeft mijn voorganger daartoe een commissie ingesteld die de werkzaamheden voortzet van de Werkgroep van Deskundigen (WGD). De WGD was een door de genoemde Minister ingestelde adviescommissie. Hierbij bied ik u - gehoord de Beraadsgroep Gezondheid en Omgeving - twee publicaties aan van de commissie over chloortrimethylsilaan en butylacetaten. Deze publicaties heb ik heden ter kennisname aan de Minister van Volksgezondheid, Welzijn en Sport en aan de Minister van Volkshuisvesting, Ruimtelijke Ordening en Milieubeheer gestuurd. Hoogachtend, w.g. prof. dr JA Knottnerus Bezoekadres Postadres Parnassusplein 5 Postbus 16052 2511 VX Den Haag 2500 BB Den Haag Telefoon (070) 340 75 20 Telefax (070) 340 75 23 Chlorotrimethylsilane Health-based recommended occupational exposure limit report of the Dutch Expert Committee on Occupational Standards, a committee of the Health Council of The Netherlands to the Minister and State Secretary of Social Affairs and Employment No. 2001/05OSH, The Hague, 15 November 2001 The Health Council of the Netherlands, established in 1902, is an independent scientific advisory body.
    [Show full text]
  • REGISTRY Database Summary Sheet (DBSS)
    SM REGISTRY/ZREGISTRY (CAS REGISTRY ) Subject • All types of inorganic and organic substances, including alloys, coordination Coverage compounds, minerals, mixtures, polymers, salts, high throughput screening (HTS) compounds as well as nucleic acid and protein sequences • Substances included in REGISTRY meet the following criteria: - Identified by CAS as coming from a reputable source, including but not limited to patents, journals, chemical catalogs, and selected substance collections on the web - Described in largely unambiguous terms - Characterized by physical methods or described in a patent document example or claim - Consistent with the laws of atomic covalent organization • Experimental and predicted property data and tags and spectra data File Type Numeric, Structure Features Alerts (SDIs) Biweekly In addition, SMARTracker, an automatic crossfile current-awareness search, (SDI XFILE) using a REGISTRY search profile in CA, HCA, ZCA, CAplus, HCAplus or ZCAplus may be run weekly or biweekly (weekly is the default). CAS Registry Keep & Share SLART Number® Identifiers ® Learning Database STN Easy Structures Record • CAS Registry Numbers • Experimental and predicted property Content • CA index names and commonly used data and tags chemical names and trade names • Spectra • Molecular formulas • List of databases and regulatory listings • Structure diagrams containing information on the substances • Sequence data • Super roles and document type SM • Alloy composition tables information from CAplus • Classes for polymers • Displayable information for 10 most recent references for substances • Ring analysis data File Size More than 140 million organic and inorganic substances; more than 71.1 million sequences (4/18) Coverage Early 1800s to the present Updates Daily Language English Database Chemical Abstracts Service Producer 2540 Olentangy River Road P.O.
    [Show full text]
  • Gas-Phase Chemistry of Methyl-Substituted Silanes in a Hot-Wire Chemical Vapour Deposition Process
    University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2013-08-27 Gas-phase Chemistry of Methyl-Substituted Silanes in a Hot-wire Chemical Vapour Deposition Process Toukabri, Rim Toukabri, R. (2013). Gas-phase Chemistry of Methyl-Substituted Silanes in a Hot-wire Chemical Vapour Deposition Process (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/26257 http://hdl.handle.net/11023/891 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Gas-phase Chemistry of Methyl-Substituted Silanes in a Hot-wire Chemical Vapour Deposition Process by Rim Toukabri A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMISTRY CALGARY, ALBERTA August, 2013 © Rim Toukabri 2013 Abstract The primary decomposition and secondary gas-phase reactions of methyl- substituted silane molecules, including monomethylsilane (MMS), dimethylsilane (DMS), trimethylsilane (TriMS) and tetramethylsilane (TMS), in hot-wire chemical vapour deposition (HWCVD) processes have been studied using laser ionization methods in combination with time of flight mass spectrometry (TOF-MS). For all four molecules, methyl radical formation and hydrogen molecule formation have been found to be the common decomposition steps on both tungsten (W) and tantalum (Ta) filaments.
    [Show full text]
  • Advances in the Understanding of Low Molecular Weight Silicon Formation and Implications for Control by Amc Filters
    APPLICATION NOTE ADVANCES IN THE UNDERSTANDING OF LOW MOLECULAR WEIGHT SILICON FORMATION AND IMPLICATIONS FOR CONTROL BY AMC FILTERS Authors: Jürgen M. Lobert, Philip W. Cate, David J. Ruede, Joseph R. Wildgoose, Charles M. Miller and John C. Gaudreau Abstract Introduction Trimethylsilanol (TMS) is a low molecular Silicon containing hydrocarbons are a class of weight / low boiling point silicon-containing, AMC causing persistent degradation of UV exposure airborne contaminant that has received increased tool optical surfaces.1,2,3 Organic silicon compounds interest over the past few years as an important are efficiently split into components by 193 nm UV cause for contamination of optical surfaces in light, commonly used in photolithography appli- lithography equipment. cations. The resulting, reactive silicon atoms can recombine with oxygen to create a layer of amor- TMS is not captured well by carbon-based filters, phous silicon dioxide on optical surfaces such as and hexamethyldisiloxane (HMDSO), even though exposure tool lenses.3,4 This haze layer can be captured well, can be converted to TMS when using difficult to remove and may require lens exchange acidic filter media commonly used for ammonia and polishing, potentially destroying optical coatings removal. TMS and HMDSO coexist in a chemical and creating substantial tool downtime and cost. equilibrium, which is affected by the acidity and The importance of TMS and related refractory moisture of their environment. species in optical degradation is one reason for This publication shows that HMDSO is converted the low level of allowable refractory compounds to TMS by acidic media at concentrations typically (100 ppt) specified in the International Technology found in cleanroom environments.
    [Show full text]
  • Grignard Reagents and Silanes
    GRIGNARD REAGENTS AND SILANES By B. Arkles REPRINTED FROM HANDBOOK OF GRIGNARD REAGENTS by G. Silverman and P. Rakita Pages 667-675 Marcel Dekker, 1996 Gelest, Inc. 612 William Leigh Drive Tullytown, Pa. 19007-6308 Phone: [215] 547-1015 Fax: [215] 547-2484 Grignard Reagents and Silanes 32 Grignard Reagents and Silanes BARRY ARKLES Gelest Inc., Tullytown, Pennsylvania I. INTRODUCTION This review considers two aspects of the interaction of Grignards with silanes. First, focusing on technologies that are still viable within the context of current organosilane and silicone technology, guidelines are provided for silicon-carbon bond formation using Grignard chemistry. Second, the use of silane-blocking agents and their stability in the presence of Grignard reagents employed in organic synthesis is discussed. II. FORMATION OF THE SILICON-CARBON BOND A. Background The genesis of current silane and silicone technology traces back to the Grignard reaction. The first practical synthesis of organosilanes was accomplished by F. Stanley Kipping in 1904 by the Grignard reaction for the formation of the silicon-carbon bond [1]. In an effort totaling 57 papers, he created the basis of modern organosilane chemistry. The development of silicones by Frank Hyde at Corning was based on the hydrolysis of Grignard-derived organosilanes [2]. Dow Corning, the largest manufacturer of silanes and silicones, was formed as a joint venture between Corning Glass, which had silicone product technology, and Dow, which had magnesium and Grignard technology, during World War II. In excess of 10,000 silicon compounds have been synthesized by Grignard reactions. Ironically, despite the versatility of Grignard chemistry for the formation of silicon-carbon bonds, its use in current silane and silicone technology has been supplanted by more efficient and selective processes for the formation of the silicon-carbon bond, notably by the direct process and hydrosilylation reactions.
    [Show full text]
  • United States Patent (19) 11) Patent Number: 4,552,973 Feldner Et Al
    United States Patent (19) 11) Patent Number: 4,552,973 Feldner et al. (45) Date of Patent: Nov. 12, 1985 54 PROCESS FOR THE PREPARATION OF 2,647,912 8/1953 Barry et al. ......................... 556/469 DMETHYLDCHLOROSLANE 2,717,257 9/1955 Bluestein ............................. 556/469 (75. Inventors: Kurt Feldner; Wolfgang Grape, both 3,384,652 5/1968 Hamilton ............................ 556/469 of Cologne, Fed. Rep. of Germany 4,477,631 5/1984 Faure et al. ......................... 556/469 Primary Examiner-Paul F. Shaver 73 Assignee: Bayer Aktiengesellschaft, Attorney, Agent, or Firm-Sprung, Horn, Kramer & Leverkusen, Fed. Rep. of Germany Woods (21) Appl. No.: 713,501 57 ABSTRACT 22 Filed: Mar. 19, 1985 A process for the preparation of dimethyldichlorosilane (30) Foreign Application Priority Data from the low-boiling and high-boiling by-products of the direct synthesis of methylchlorosilane, comprising Mar. 23, 1984 (DE) Fed. Rep. of Germany ....... 3410644 reacting methyltrichlorosilane simultaneously with the 51) Int. Cl." ................................................ C07F 7/12 low-boiling components having a high content of 52 U.S.C. .................................................... 556/469 methyl groups and with the high-boiling non-cleavable 58 Field of Search ......................................... 556/469 components, in the presence of a catalyst, at a tempera 56) References Cited ture between about 250 C. and 400 C. and under a U.S. PATENT DOCUMENTS pressure of up to 100 bar. 2,647,136 7/1953 Sauer ................................... 556/469 4 Claims, No Drawings 4,552,973 1. 2 minum chloride which, however, is converted to the PROCESS FOR THE PREPARATION OF known catalyst AlCl3 by hydrogen chloride gas fed DIMETHYTLDICHLOROSLANE simultaneously into the reaction mixture.
    [Show full text]
  • University of California Riverside
    UNIVERSITY OF CALIFORNIA RIVERSIDE Thermal Decomposition of Molecules Relevant to Combustion and Chemical Vapor Deposition by Flash Pyrolysis Time-of-Flight Mass Spectrometry A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Chemistry by Jessy Mario Lemieux December 2013 Dissertation Committee: Dr. Jingsong Zhang, Chairperson Dr. Christopher Bardeen Dr. David Bocian Copyright by Jessy Mario Lemieux 2013 The Dissertation of Jessy Mario Lemieux is approved: Committee Chairperson University of California, Riverside ACKNOWLEDGMENTS Professor Jingsong Zhang Dr. Steven Chambreau Dr. Kevin Weber Paul Jones Jeff Lefler Mike Fournier Stan Sheldon Professor Christopher Bardeen Professor David Bocian iv DEDICATION This work is dedicated to my parents who taught me the value of curiosity and learning and have always been there for me. v ABSTRACT OF THE DISSERTATION Thermal Decomposition of Molecules Relevant to Combustion and Chemical Vapor Deposition by Flash Pyrolysis Time-of-Flight Mass Spectrometry by Jessy Mario Lemieux Doctor of Philosophy, Graduate Program in Chemistry University of California, Riverside, December 2013 Dr. Jingsong Zhang, Chairperson Flash pyrolysis coupled with vacuum-ultraviolet photoionization time-of-flight mass spectrometry was used to study the thermal decomposition mechanisms of molecules relevant to fuel combustion and the chemical vapor deposition (CVD) of SiGe, SiC, and GeC. For combustion research, the thermal decomposition of benzyl radical, n- alkanes CnH2n+2 (n = 5-8 and 10), 1-butyl radical, and 1-pentyl radical was performed. Benzyl was confirmed to decompose primarily by ejection of H atom after significant isomerization with loss of methyl observed as a minor decomposition pathway.
    [Show full text]
  • Kinetics of the Thermal Decomposition of Tetramethylsilane Behind the Reflected Shock Waves Between 1058 and 1194 K
    J. Chem. Sci. Vol. 128, No. 4, April 2016, pp. 573–588. c Indian Academy of Sciences. DOI 10.1007/s12039-016-1046-8 Kinetics of the thermal decomposition of tetramethylsilane behind the reflected shock waves between 1058 and 1194 K A PARANDAMAN and B RAJAKUMAR∗ Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India e-mail: [email protected] MS received 16 September 2015; revised 31 December 2015; accepted 4 January 2016 Abstract. Thermal decomposition of tetramethylsilane (TMS) diluted in argon was studied behind the reflected shock waves in a single pulse shock tube (SPST) in the temperature range of 1058–1194 K. The major products formed in the decomposition are methane (CH4) and ethylene (C2H4); whereas ethane and propy- lene were detected in lower concentrations. The decomposition of TMS seems to be initiated via Si-C bond scission by forming methyl radicals (CH3) and trimethylsilyl radicals ((CH3)3Si). The total rate coefficients obtained for the decomposition of TMS were fit to Arrhenius equation in two different temperature regions 1058–1130 K and 1130–1194 K. The temperature dependent rate coefficients obtained are ktotal (1058–1130 K) 18 −1 −1 6 = (4.61 ± 0.70) ×10 exp (−(79.9 kcal mol ± 3.5)/RT) s ,ktotal (1130-1194 K) = (1.33 ± 0.19) ×10 exp −1 −1 (−(15.3 kcal mol ± 3.5)/RT) s . The rate coefficient for the formation of CH4 is obtained to be kmethane (1058–1194 K) = (4.36 ± 1.23) ×1014 exp (−(61.9 kcal mol−1 ± 4.9)/RT) s−1.
    [Show full text]
  • Decomposition of Hexamethyldisilazane on Hot Metal Filaments and Its Gas-Phase Chemistry in a Hot-Wire Chemical Vapor Deposition Reactor
    University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2019-09-04 Decomposition of Hexamethyldisilazane on Hot Metal Filaments and its Gas-phase Chemistry in a Hot-wire Chemical Vapor Deposition Reactor Ampong, Eric Ampong, E. (2019). Decomposition of Hexamethyldisilazane on Hot Metal Filaments and its Gas-phase Chemistry in a Hot-wire Chemical Vapor Deposition Reactor (Unpublished master's thesis). University of Calgary, Calgary, AB. http://hdl.handle.net/1880/110892 master thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Decomposition of Hexamethyldisilazane on Hot Metal Filaments and its Gas-phase Chemistry in a Hot-wire Chemical Vapor Deposition Reactor by Eric Ampong A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULLFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE PROGRAM IN CHEMISTRY CALGARY, ALBERTA SEPTEMBER, 2019 © Eric Ampong 2019 Abstract Hot-wire chemical vapor deposition (HWCVD) has been used to produce silicon- containing thin films, nanomaterials, and functional polymer coatings for applications in microelectronic and photovoltaic devices. Silicon carbonitride (SiCyNz) thin films, deposited by HWCVD, have found a wide range of applications due to their nonstoichiometric component that exhibits unique properties from a combination of SiC and Si3N4 binary compounds.
    [Show full text]
  • List of Lists
    United States Office of Solid Waste EPA 550-B-10-001 Environmental Protection and Emergency Response May 2010 Agency www.epa.gov/emergencies LIST OF LISTS Consolidated List of Chemicals Subject to the Emergency Planning and Community Right- To-Know Act (EPCRA), Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and Section 112(r) of the Clean Air Act • EPCRA Section 302 Extremely Hazardous Substances • CERCLA Hazardous Substances • EPCRA Section 313 Toxic Chemicals • CAA 112(r) Regulated Chemicals For Accidental Release Prevention Office of Emergency Management This page intentionally left blank. TABLE OF CONTENTS Page Introduction................................................................................................................................................ i List of Lists – Conslidated List of Chemicals (by CAS #) Subject to the Emergency Planning and Community Right-to-Know Act (EPCRA), Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and Section 112(r) of the Clean Air Act ................................................. 1 Appendix A: Alphabetical Listing of Consolidated List ..................................................................... A-1 Appendix B: Radionuclides Listed Under CERCLA .......................................................................... B-1 Appendix C: RCRA Waste Streams and Unlisted Hazardous Wastes................................................ C-1 This page intentionally left blank. LIST OF LISTS Consolidated List of Chemicals
    [Show full text]
  • Spectroscopy
    11 Spectroscopy Infrared (top) and nuclear magnetic resonance (bottom) image of heart with CAD, coronary artery disease. Inset: A model of heme, the part of the protein hemoglobin that binds oxygen. The infrared technique detects deoxygenated hemoglobin, which tends to occur in high levels in blocked arteries. Both techniques represent noninvasive methods for medical imaging of the body. (top: Image courtesy of the National Research Council Canada; bottom: © Sovereign, © ISM/Phototake-All rights reserved.) KEY QUESTIONS 11.1 What Is Electromagnetic Radiation? 11.12 What Is 13C-NMR Spectroscopy, and How Does It 1 11.2 What Is Molecular Spectroscopy? Differ from H-NMR Spectroscopy? 11.3 What Is Infrared Spectroscopy? 11.13 How Do We Solve an NMR Problem? 11.4 How Do We Interpret Infrared Spectra? HOW TO 11.5 What Is Nuclear Magnetic Resonance? 11.1 How to Approach Infrared Spectroscopy Structure 11.6 What Is Shielding? Determination Problems 11.7 What Is an NMR Spectrum? 11.2 How to Determine Whether an Atomic Nucleus Has 11.8 How Many Resonance Signals Will a Compound a Spin (Behaves as If It Were a Tiny Bar Magnet) Yield in Its NMR Spectrum? 11.9 What Is Signal Integration? CHEMICAL CONNECTIONS 11.10 What Is Chemical Shift? 11A Infrared Spectroscopy: A Window on Brain Activity 11.11 What Is Signal Splitting? 11B Magnetic Resonance Imaging DETERMINING THE MOLECULAR structure of a compound is a central theme in science. In medicine, for example, the structure of any drug must be known before the drug can be ap- proved for use in patients.
    [Show full text]