(12) United States Patent (10) Patent No.: US 8,753,759 B2 Liao (45) Date of Patent: *Jun
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Understanding the Bonding of Second Period Diatomic Molecules Spdf Vs MCAS
Understanding the Bonding of Second Period Diatomic Molecules Spdf vs MCAS By Joel M Williams (text and images © 2013) The html version with updates and higher resolution images is at the author’s website (click here) Abstract The current spdf and MO modeling of chemical molecules are well-established, but do so by continuing to assume that non-classical physics is operating. The MCAS electron orbital model is an alternate particulate model based on classical physics. This paper describes its application to the diatomic molecules of the second period of the periodic table. In doing so, it addresses their molecular electrostatics, bond strengths, and electron affinities. Particular attention is given to the anomalies of the carbon diatom. Questions are raised about the sensibleness of the spdf model’s spatial ability to contain two electrons on an axis between diatoms and its ability to form π-bonds from parallel p-orbitals located over the nuclei of each atom. Nitrogen, carbon monoxide, oxygen, and fluorine all have the same inter-nuclei bonding: all “triple bonds” of varying strength caused by different numbers of anti-bonding electrons. The spdf model was devised for single atoms by physicists and mathematicians. Kowtowing to them, chemists produce hybrid orbitals to explain how atoms could actually form molecules. Drawing these hybrids and meshing them on paper might look great, but, constrained to measured interatomic physical dimensions and electrostatic interactions, bonding based on the spdf-hybrids (sp, sp2, sp3) is illogical. To have even one electron occupy the “bond” region between the nuclei of diatomic molecules, at the expense of reduced coverage elsewhere, does not make sense for stable molecules. -
Discharge Plasmas of Molecular Gases
/ J ¥4~r~~~: 'o j~ ~7 ~,~U;~I u t= ~]f~LL*~ ~~~~~~; 4. Isotope Separation in Discharge Plasmas of Molecular Gases EZOUBTCHENKO, Alexandre N.t, AKATSUKA Hiroshi and SUZUKI Masaaki Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan (Received 25 December 1997) Abstract We review the theoretical principles and the experimental methods of isotope separation achieved through the use of discharge plasmas of molecular gases. Isotope separation has been accomplished in various plasma chemical reactions. It is experimentally and theoretically shown that a state of non- equilibrium in the plasmas, especially in the vibrational distribution functions, is essential for the isotope redistribution in the reagents and products. Examples of the reactions, together with the isotope separ- ation factors known up to the present time, are shown to separate isotopic species of carbon, nitrogen and oxygen molecules in the plasma phase, generated by glow discharge and microwave discharge. Keywords: isotope separation, vibrational nonequilibrium, glow discharge, microwave discharge, plasma chemistry 4.1 Introduction isotopic species will be redistributed between the rea- Plasmas generated by electric discharge of molecu- gents and the products. We can elaborate a new lar gases under moderate pressures (10 Torr < p < method of the plasma isotope separation for light ele- 200 Torr) are usually in a state of nonequilibrium. We ments . can define various temperatures according to the kine- There were a few experimental studies of isotope tics of various particles in such plasmas, for example, separation phenomena in the nonequilibrium electric electron temperature ( T*), gas translational temperature discharge. Semiokhin et al. measured C02 enrichment ( To), gas rotational temperature ( TR) and vibrational in i3C02 and 12C160180 with a separation factor a ~ temperature ( Tv), where the relationships T* > Tv ;~ 1.01 in the C02 Silent (barrier) discharge in the pres- TR- To usually hold. -
©2018 Alexander Hook ALL RIGHTS RESERVED
©2018 Alexander Hook ALL RIGHTS RESERVED A DFT STUDY OF HYDROGEN ABSTRACTION FROM LIGHT ALKANES: Pt ALLOY DEHYDROGENATION CATALYSTS AND TIO2 STEAM REFORMING CATALYSTS By ALEXANDER HOOK A dissertation submitted to the School of Graduate Studies Rutgers, The State University of New Jersey In partial fulfillment of the requirements For the degree of Doctor of Philosophy Graduate Program in Chemical and Biochemical Engineering Written under the direction of Fuat E. Celik And approved by __________________________ __________________________ __________________________ __________________________ New Brunswick, New Jersey May, 2018 ABSTRACT OF THE DISSERTATION A DFT STUDY OF HYDROGEN ABSTRACTION FROM LIGHT ALKANES: Pt ALLOY DEHYDROGENATION CATALYSTS AND TiO2 STEAM REFORMING CATALYSTS By ALEC HOOK Dissertation Director: Fuat E. Celik Sustainable energy production is one of the biggest challenges of the 21st century. This includes effective utilization of carbon-neutral energy resources as well as clean end-use application that do not emit CO2 and other pollutants. Hydrogen gas can potentially solve the latter problem, as a clean burning fuel with very high thermodynamic energy conversion efficiency in fuel cells. In this work we will be discussing two methods of obtaining hydrogen. The first is as a byproduct of light alkane dehydrogenation where we obtain a high value olefin along with hydrogen gas. The second is in methane steam reforming where hydrogen is the primary product. Chapter 1 begins by introducing the reader to the current state of the energy industry. Afterwards there is an overview of what density functional theory (DFT) is and how this computational technique can elucidate and complement laboratory experiments. It will also contain the general parameters and methodology of the VASP software package that runs the DFT calculations. -
Chapter 10 Theories of Electronic Molecular Structure
Chapter 10 Theories of Electronic Molecular Structure Solving the Schrödinger equation for a molecule first requires specifying the Hamiltonian and then finding the wavefunctions that satisfy the equation. The wavefunctions involve the coordinates of all the nuclei and electrons that comprise the molecule. The complete molecular Hamiltonian consists of several terms. The nuclear and electronic kinetic energy operators account for the motion of all of the nuclei and electrons. The Coulomb potential energy terms account for the interactions between the nuclei, the electrons, and the nuclei and electrons. Other terms account for the interactions between all the magnetic dipole moments and the interactions with any external electric or magnetic fields. The charge distribution of an atomic nucleus is not always spherical and, when appropriate, this asymmetry must be taken into account as well as the relativistic effect that a moving electron experiences as a change in mass. This complete Hamiltonian is too complicated and is not needed for many situations. In practice, only the terms that are essential for the purpose at hand are included. Consequently in the absence of external fields, interest in spin- spin and spin-orbit interactions, and in electron and nuclear magnetic resonance spectroscopy (ESR and NMR), the molecular Hamiltonian usually is considered to consist only of the kinetic and potential energy terms, and the Born- Oppenheimer approximation is made in order to separate the nuclear and electronic motion. In general, electronic wavefunctions for molecules are constructed from approximate one-electron wavefunctions. These one-electron functions are called molecular orbitals. The expectation value expression for the energy is used to optimize these functions, i.e. -
Diatomic Carbon Measurements with Laser-Induced Breakdown Spectroscopy
University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 5-2015 Diatomic Carbon Measurements with Laser-Induced Breakdown Spectroscopy Michael Jonathan Witte University of Tennessee - Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Atomic, Molecular and Optical Physics Commons, and the Plasma and Beam Physics Commons Recommended Citation Witte, Michael Jonathan, "Diatomic Carbon Measurements with Laser-Induced Breakdown Spectroscopy. " Master's Thesis, University of Tennessee, 2015. https://trace.tennessee.edu/utk_gradthes/3423 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Michael Jonathan Witte entitled "Diatomic Carbon Measurements with Laser-Induced Breakdown Spectroscopy." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Physics. Christian G. Parigger, Major Professor We have read this thesis and recommend its acceptance: Horace Crater, Joseph Majdalani Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Diatomic Carbon Measurements with Laser-Induced Breakdown Spectroscopy A Thesis Presented for the Master of Science Degree The University of Tennessee, Knoxville Michael Jonathan Witte May 2015 c by Michael Jonathan Witte, 2015 All Rights Reserved. -
Immobilization of Carbonylnickel Complexes: a Solid-State NMR Study
1814 Inorg. Chem. 1996, 35, 1814-1819 Immobilization of Carbonylnickel Complexes: A Solid-State NMR Study K. D. Behringer and J. Blu1mel* Anorganisch-chemisches Institut der TU Mu¨nchen, Lichtenbergstrasse 4, 85747 Garching, Germany ReceiVed June 15, 1995X Silica is commonly modified with bifunctional phosphines like PPh2CH2CH2Si(OEt)3 prior to immobilization of catalysts. Here, besides PPh2(CH2)3Si(OEt)3, ligands that are more stable toward oxidation, namely PPh2(C6H4)- Si(OEt)3, PPh2(C6H4)SiMe2(OEt), and PPh2(CH2)4OH, are applied. The di- and tricarbonylnickel complexes of these ligands are synthesized, characterized by 61Ni, 31P, 13C, and 1H NMR and IR spectroscopy, and immobilized on silica. Alternatively, the corresponding phosphine-modified silicas are treated with Ni(CO)4. The obtained materials are investigated by 31P and 13C solid-state NMR spectroscopy. Di- and tricarbonylnickel species can be distinguished by their different chemical shift anisotropies and also by their IR data. While the first route allows immobilization of both di- and tricarbonylnickel complexes, reaction of surface-bound phosphines with Ni(CO)4 gives the tricarbonyl species exclusively. Among the different ligands, PPh2(CH2)4OH has optimal qualities: It gives high surface coverages without oxidation or cross-linking, and therefore narrow NMR lines, and it allows 13C CP/MAS NMR spectroscopy. 1. Introduction developed. The sol-gel process for instance provides the option of a tailored silica support material with a high loading of Immobilized catalysts are of growing interest, because they catalyst. It has been successfully applied for example by can, in principle, combine all the advantages of heterogeneous 14,15 16,17 1-4 Lindner and Schubert. -
Fullerenes and Pahs: a Novel Model Explains Their Formation Via
Fullerenes and PAHs: A Novel Model Explains their Formation via Sequential Cycloaddition Reactions Involving C2 Dimers Sylvain L. Smadja [email protected] 10364 Almayo Ave., Suite 304 Los Angeles, CA 90064 “Cove” region closure C20 bowl + 10C2 creates pentagonal ring C50 + 5C2 [2 + 2 + 2] [4 + 2] Cycloadditions Cycloadditions Cage 5C 5C 2 2 closure “Cove” region C40 C50 C60 Buckministerfullerene ABSTRACT: Based on a new understanding of the nature of the bonding in the C2 dimer, a novel bottom-up model is offered that can explain the growth processes of fullerenes and polycyclic aromatic hydrocarbons (PAHs). It is shown how growth sequences involving C2 dimers, that take place in carbon vapor, combustion systems, and the ISM, could give rise to a variety of bare carbon clusters. Among the bare carbon clusters thus formed, some could lead to fullerenes, while others, after hydrogenation, could lead to PAHs. We propose that the formation of hexagonal rings present in these bare carbon clusters are the result of [2+2+2] and [4+2] cycloaddition reactions that involve C2 dimers. In the C60 and C70 fullerenes, each of the twelve pentagons is surrounded by five hexagons and thereby “isolated” from each other. To explain why, we suggest that in bowl-shaped clusters the pentagons can form as the consequence of closures of “cove regions” that exist between hexagonal rings, and that they can also form during cage-closure, which results in the creation of six “isolated” pentagonal rings, and five hexagonal rings. The proposed growth mechanisms can account for the formation of fullerene isomers without the need to invoke the widely used Stone-Wales rearrangement. -
Arxiv:2106.07647V1 [Physics.Chem-Ph] 14 Jun 2021 Molecules Such As Water (Viti Et Al.(1997), Polyansky JPL (Pearson Et Al
Draft version June 16, 2021 Typeset using LATEX twocolumn style in AASTeX63 A Large-scale Approach to Modelling Molecular Biosignatures: The Diatomics Thomas M. Cross,1 David M. Benoit,1 Marco Pignatari,1, 2, 3, 4 and Brad K. Gibson1 1E. A. Milne Centre for Astrophysics, Department of Physics and Mathematics, University of Hull, HU6 7RX, United Kingdom 2Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklos ut 15-17, H-1121 Budapest, Hungary 3NuGrid Collaboration, http:// nugridstars.org 4Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements Submitted to ApJ ABSTRACT This work presents the first steps to modelling synthetic rovibrational spectra for all molecules of astrophysical interest using the new code Prometheus. The goal is to create a new comprehensive source of first-principles molecular spectra, thus bridging the gap for missing data to help drive future high-resolution studies. Our primary application domain is on molecules identified as signatures of life in planetary atmospheres (biosignatures). As a starting point, in this work we evaluate the accuracy of our method by studying the diatomics molecules H2,O2,N2 and CO, all of which have well-known spectra. Prometheus uses the Transition-Optimised Shifted Hermite (TOSH) theory to account for anharmonicity for the fundamental ν = 0 ! ν = 1 band, along with thermal profile modeling for the rotational transitions. We present a novel new application of the TOSH theory with regards to rotational constants. Our results show that this method can achieve results that are a better approximation than the ones produced through the basic harmonic method. -
Chemical Dynamics of Triacetylene Formation and Implications to the Synthesis of Polyynes in Titan’S Atmosphere
Chemical dynamics of triacetylene formation and implications to the synthesis of polyynes in Titan’s atmosphere X. Gua,Y.S.Kima, R. I. Kaisera,1, A. M. Mebelb, M. C. Liangc,d,e, and Y. L. Yungf aDepartment of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822; bDepartment of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 ; cResearch Center for Environmental Changes, Academia Sinica, Taipei 115, Taiwan; dGraduate Institute of Astronomy, National Central University, Jhongli 320, Taiwan; eInstitute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan; and fDivision of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 Edited by William Klemperer, Harvard University, Cambridge, MA, and approved August 12, 2009 (received for review January 16, 2009) For the last four decades, the role of polyynes such as diacetylene Therefore, an experimental investigation of these elementary (HCCCCH) and triacetylene (HCCCCCCH) in the chemical evolution reactions under single collision conditions is desirable (16–18). of the atmosphere of Saturn’s moon Titan has been a subject of In this article, we report the results of a crossed molecular vigorous research. These polyacetylenes are thought to serve as an beam reaction of the isotope variant of the elementary reaction 2⌺ϩ 1⌺ϩ UV radiation shield in planetary environments; thus, acting as of ethynyl radicals (C2H; X ) with diacetylene (C4H2;X g ). prebiotic ozone, and are considered as important constituents of These results are combined with electronic structure calculations the visible haze layers on Titan. However, the underlying chemical and photochemical modeling to unravel the formation and role 1⌺ϩ processes that initiate the formation and control the growth of of the organic transient molecule triacetylene (C6H2;X g )in polyynes have been the least understood to date. -
Diffuse Atomic and Molecular Clouds
ANRV284-AA44-09 ARI 28 July 2006 14:14 Diffuse Atomic and Molecular Clouds Theodore P. Snow1 and Benjamin J. McCall2 1Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, Colorado 80309; email: [email protected] 2Departments of Chemistry and Astronomy, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; email: [email protected] Annu. Rev. Astron. Astrophys. Key Words 2006. 44:367–414 interstellar medium, interstellar molecules, spectroscopy First published online as a Review in Advance on June 5, 2006 Abstract by UNIVERSITY OF ILLINOIS on 09/05/06. For personal use only. The Annual Review of Diffuse interstellar clouds have long been thought to be relatively devoid of molecules, Astrophysics is online at because of their low densities and high radiation fields. However, in the past ten years astro.annualreviews.org or so, a plethora of polyatomic molecules have been observed in diffuse clouds, via doi: 10.1146/ their rotational, vibrational, and electronic transitions. In this review, we propose Annu. Rev. Astro. Astrophys. 2006.44:367-414. Downloaded from arjournals.annualreviews.org annurev.astro.43.072103.150624 a new systematic classification method for the different types of interstellar clouds: Copyright c 2006 by diffuse atomic, diffuse molecular, translucent, and dense. We review the observa- Annual Reviews. All rights tions of molecules (both diatomic and polyatomic) in diffuse clouds and discuss how reserved molecules can be utilized as indicators of the physical and chemical conditions within 0066-4146/06/0922- these clouds. We review the progress made in the modeling of the chemistry in these 0367$20.00 clouds, and the (significant) challenges that remain in this endeavor. -
Pyrolysis of Jet Propellants and Oxidation Of
Florida International University FIU Digital Commons FIU Electronic Theses and Dissertations University Graduate School 5-15-2018 Pyrolysis of Jet Propellants and Oxidation of Polycyclic Aromatic Radicals with Molecular Oxygen: Theoretical Study of Potential Energy Surfaces, Mechanisms, and Kinetics Daniel E. Belisario-Lara [email protected] DOI: 10.25148/etd.FIDC006814 Follow this and additional works at: https://digitalcommons.fiu.edu/etd Part of the Physical Chemistry Commons Recommended Citation Belisario-Lara, Daniel E., "Pyrolysis of Jet Propellants and Oxidation of Polycyclic Aromatic Radicals with Molecular Oxygen: Theoretical Study of Potential Energy Surfaces, Mechanisms, and Kinetics" (2018). FIU Electronic Theses and Dissertations. 3819. https://digitalcommons.fiu.edu/etd/3819 This work is brought to you for free and open access by the University Graduate School at FIU Digital Commons. It has been accepted for inclusion in FIU Electronic Theses and Dissertations by an authorized administrator of FIU Digital Commons. For more information, please contact [email protected]. FLORIDA INTERNATIONAL UNIVERSITY Miami, Florida PYROLYSIS OF JET PROPELLANTS AND OXIDATION OF POLYCYCLIC AROMATIC RADICALS WITH MOLECULAR OXYGEN: THEORETICAL STUDY OF POTENTIAL ENERGY SURFACES, MECHANISMS, AND KINETICS A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in CHEMISTRY by Daniel Belisario-Lara 2018 To: Dean Michael R. Heithaus College of Arts, Sciences and Education This dissertation, written by Daniel Belisario-Lara, and entitled Pyrolysis of Jet Propellants and Oxidation of Polycyclic Aromatic Radicals with Molecular Oxygen: Theoretical Study of Potential Energy Surfaces, Mechanisms, and Kinetics, having been approved in respect to style and intellectual content, is referred to you for judgment. -
Novel Contributions to the Solid-State Chemistry of Diazenides” 05/2009–11/2009 Master Thesis (Inorganic Chemistry) Ludwig-Maximilian University Munich (Prof
Dissertation zur Erlangung des Doktorgrades der Fakultät für Chemie und Pharmazie der Ludwig-Maximilians-Universität München Novel Contributions to the Solid-State Chemistry of Diazenides Sebastian Bernhard Schneider aus München, Deutschland 2013 Erklärung Diese Dissertation wurde im Sinne von § 7 der Promotionsordnung vom 28. November 2011 von Herrn Prof. Dr. Wolfgang Schnick betreut. Eidesstattliche Versicherung Diese Dissertation wurde eigenständig und ohne unerlaubte Hilfe erarbeitet. München, 11.11.2013 …………………………………… (Sebastian Bernhard Schneider) Dissertation eingereicht am 11.11.2013 1. Gutachter: Prof. Dr. Wolfgang Schnick 2. Gutachter: Prof. Dr. Dirk Johrendt Mündliche Prüfung am 16.12.2013 To my family ACKNOWLEDGEMENTS First, I would like to express my gratitude to my supervisor Prof. Dr. Wolfgang Schnick for the opportunity to do my PhD under his guidance. Throughout the entire work, I appreciated his extraordinary expertise, the given freedom in research and writing and the support at any time. For being the co-referee of my thesis, I thank Prof. Dr. Dirk Johrendt. I am thankful to Prof. Dr. Konstantin Karaghiosoff, PD Dr. Markus Lackinger, Prof. Dr. Hans-Christian Böttcher, and Prof. Dr. Jörn Schmedt a. d. Günne for being available as examiners in my viva-voce. In addition, I have to thank various co-workers spread all over Germany and Europe. Hereby, special thanks go to • Volker L. Deringer, Dr. Ralf P. Stoffel as well as Prof. Dr. Richard Dronskowski (RWTH Aachen, Germany) for their long-lasting support with numerous theoretical calculations concerning novel diazenide compounds and for their ongoing enthusiasm until we found the final ground state. • Dr. Lkhamsuren Bayarjargal, Dr.