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Creator | Title | Description | Subject | Date |
176 |
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Truong, Thanh | Combined reaction class approach with integrated molecular orbital + molecular orbital (IMOMO) methodology: a practical tool for kinetic modeling | We present a new practical computational methodology for predicting thermal rate constants of reactions involving large molecules or a large number of elementary reactions in the same class. This methodology combines the integrated molecular orbital1molecular orbital (IMOMO) approach with our rece... | IMOMO; Kinetic modeling; Thermal rate constants | 2000 |
177 |
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Miller, Joel Steven | Three-dimensional network-structured cyanide-based magnets | Introduction Magnets based on metal oxides have been important for hundreds of years. Magnetite, Fe3O4, Co-doped (y)-Fe2O3, and CrO2 are important examples. The oxide (O2-) bridge between the magnetic metal ions has filled p orbitals (Figure 1a) that provide the pathway for strong spin coup... | Magnetic; Ferrimagnetic; Magnetization | 2000 |
178 |
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Voth, Gregory Alan | Ab initio calculations of reactive pathways for ?-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (?-HMX) | Using the BLYP and B3LYP level of density functional theory, four possible decomposition reaction pathways of HMX in the gas phase were investigated: N?NO2 bond dissociation, HONO elimination, C?N bond scission of the ring, and the concerted ring fission. The energetics of each of these four mechan... | Ab initio calculations; Reactive pathways; HMX | 2000 |
179 |
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Wight, Charles Albert | Estimating realistic confidence intervals for the activation energy determined from thermoanalytical measurements | A statistical procedure is proposed for estimating realistic confidence intervals for the activation energy determined by using an advanced isoconversional method. Nine sets of five thermogravimetric measurements have been produced for the process of gassification of ammonium nitrate at five differe... | Thermoanalysis; Activation energy; Isoconversional method | 2000 |
180 |
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Orendt, Anita; Pugmire, Ronald J. | Carbon-13 chemical shift tensors in polycyclic aromiatic compounds. 9. Biphenylene | The principal values of the 13C chemical-shift tensors of natural abundance biphenylene were measured at room temperature with the FIREMAT experiment. Of 18 crystallographically distinct positions (three sets of six congruent carbons each), the three primary bands have been resolved into seven singl... | Carbon-13; Chemical-shift tensors; Biphenylene; Polycyclic aromiatic compounds; FIREMAT | 2000 |
181 |
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Wight, Charles Albert | Competitive vaporization and decomposition of liquid RDX | The thermal decomposition of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Activation energies as a function of the extent of conversion, ?, have been determined by model-free isoconversional analysis o... | Liquid RDX; Competitive vaporization; Thermal decomposition; Differential scanning calorimetry | 2000 |
182 |
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Truong, Thanh | Thermal rate constants of the NO2 fission reaction of gas phase ?-HMX: a direct ab initio dynamics study | The NO2 fission reaction of gas phase ?-HMX has been studied using a direct ab initio method within the framework of microcanonical variational transition state theory (?VT). The potential energy calculations were calculated using the hybrid nonlocal B3LYP density functional theory with the cc-pVDZ ... | HMX; Fission reaction; Thermal rate constants; Microcanonical variational transition state theory | 2000 |
183 |
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Voth, Gregory Alan | Electronic structure calculation of the structures and energies of the three pure polymorphic forms of crystalline HMX | The molecular structures and energetic stabilities of the three pure polymorphic forms of crystalline HMX were calculated using a first-principles electronic-structure method. The computations were performed using the local density approximation in conjunction with localized "fireball" orbitals and ... | HMX; Crystalline HMX; Molecular geometry | 2000 |
184 |
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Truong, Thanh | Direct ab initio dynamics studies of N + H2<-->NH + H reaction | Kinetics of the N+H2<-->NH+H reaction have been studied using a direct ab initio dynamics method. Potential energy surface for low electronic states have been explored at the QCISD/ cc-pVDZ level of theory. We found the ground-state reaction is N(4S)+H2-->NH(3Σ-)+H. Thermal rate constants for this ... | Ab initio dynamics; Potential energy surfaces; Minimum energy path; Ground-state reaction; Rate constants | 2000 |
185 |
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Truong, Thanh | Reaction class transition state theory: hydrogen abstraction reactions by hydrogen atoms as test cases | We present a new method called Reaction Class Transition State Theory (RC-TST) for estimating thermal rate constants of a large number of reactions in a class. This method is based on the transition state theory framework within the reaction class approach. Thermal rate constants of a given reacti... | Transition state theory; Hydrogen | 2000 |
186 |
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Miller, Joel Steven | Ferrimagnetic ordering of a methylthio-substituted planar porphyrin based electron transfer salt, octakis(2,3,7,8,12,13,17,18-methylthio)porphyrinatomanganese(III) tetracyanoethanide | The direct redox reaction between tetracyanoethylene (TCNE) and a planar porphyrinatomanganese(II), octakis(2,3,7,8,12,13,17,18-methylthio)porphyrinatomanganese(II), MnIIOMTP, produced a polymeric electron transfer salt (ETS), that has been structurally and magnetically characterized. The ETS belon... | Magnetic; Temperature; Coupling | 2000 |
187 |
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Miller, Joel Steven | Manganese(II)octabutoxynaphthalocyanine and its ferrimagnetic electron-transfer salt with TCNE | The magnetic susceptibility (x) of 1,6,10,15,19,25,28,32- octa-n-butoxynaphthalocyaninatomanganese(III) tetracyanoethanide can be fit to a Curie-Weiss expression with O=54 K for T>150 K, and the xT(T) data are consistent with linear chains and can be fit to a Seiden expression for alternating S=2 a... | Magnetic; Ordering; Magnetization | 2000 |
188 |
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Miller, Joel Steven; Epstein, Arthur J. | Photoinduced magnetism, dynamics, and cluster glass behavior of a molecule-based magnet | The dynamic susceptibility study of photoinduced magnetism in a molecule-based magnet, (K1-2xCo1+x [Fe(CN)6]. yH2O (0.2<_x<_0.4,y-5), is reported. Upon excitation with visible light the material has substantial changes in linear and nonlinear ac susceptibility and dc magnetization. The results d... | Magnetization; Light; Magnetometer | 2000 |
189 |
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Miller, Joel Steven; Liao, Yi | Synthesis and structure of an asymmetric copper(I) dimer with two-coordinate and four-coordinate copper(I) sites | Copper(I) coordination compounds have been studied intensively due to their biological relevance, catalytic properties, and theoretical interests. Numerous mononuclear and polynuclear copper(I) complexes with different coordination numbers have been prepared and characterized. Recently the possible ... | Polynuclear; Nitrogens; Electrons | 2000 |
190 |
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Armentrout, Peter B. | Activation of methane by size-elected iron cluster cations, Fen+ (n=2-15): cluster-CHx (x=0-3) bond energies and reaction mechanisms | The kinetic energy dependences of the reactions of Fen + (n=2 - 15) with CD4 are studied in a guided ion beam tandem mass spectrometer over the energy range of 0-10 eV. All reactions exhibit thresholds and two main products, FenD+ and FenCD2+, are formed. | Metal clusters; Iron ions; Bond energies; Dehydrogenation; Endothermic reactions; Transition metal ions | 2001 |
191 |
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Miller, Joel Steven | Ferrimagnetic ordering of one-dimensional N,N'-dicyanoquinone diimine (DCNQI) electron transfer salts with porphyrinatomanganese(II)* | The redox reaction between N,N'-dicyanoquinone diimines (DCNQIs) and porphyrinatomanganese(II) produced electron transfer salts (ETSs), [MnIIITMesP]+[DMeO-DCNQI]-. 1 (MnIIITMesP=meso-tetrakis(2,4,6- trimethylphenyl)porphyrinatomanganese(III), DMeO-DCNQI=2,5-dimethoxy-N,N'-dicyanoquinone diimine) an... | Transitions; Interactions; Magnetic | 2001 |
192 |
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Armentrout, Peter B. | Guided ion beam study of collision-induced dissociation dynamics: integral and differential cross sections | The low energy collision-induced dissociation (CID) of Cr(CO)6+ with Xe is investigated using a recently modified guided ion beam tandem mass spectrometer, in the energy range from 0 to 5 eV in the center-of-mass (CM) frame. The additions to the instrument, updated with a double octopole system, and... | Collision-induced dissociation; Bond energies; Chromium carbonyl; Xenon | 2001 |
193 |
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Morse, Michael David | Electronic structure of the 4d transition metal carbides: dispersed fluorescence spectroscopy of MoC, RuC, and PdC | Dispersed fluorescence studies of the diatomic molecules MoC, RuC, and PdC are reported. New states identified in MoC and RuC are the [...]2?112?1, 3,1?2 states and the [...]2? 312?1, 1?2 state, respectively. Five states re observed by dispersed fluorescence in PdC. The ground state is found to be [... | | 2001 |
194 |
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Miller, Joel Steven | [Et4N]2[TCNE]2 (TCNE = tetracyanoethylene) - an example of an exceptionally long 2.827 Ã CC bond | Interest in organic compounds exhibiting unusually long CC bonds has been the subject of several recent studies.1-3 The longest sp3-sp3 C-C single bond reported to date is 1.73 A°,1,2 whereas several [TCNE]22- (TCNE = tetracyanoethylene) dimers have been recently reported to form cation-assisted, l... | Synthesis; Crystal; Solution | 2001 |
195 |
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Truong, Thanh; Sarofim, Adel F. | Quantum mechanic study of high molecular mass compounds in combustion conditions | Experimental studies on soot formation show interesting trends that can only be explained by a polymerization pathway. These experimental findings are reviewed and ab initio calculations are used to evaluate possible mechanistic pathways. A sequence of chemical reactions between aromatic compounds a... | High molecular mass compounds; Quantum mechanics; Soot formation | 2001 |
196 |
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Miller, Joel Steven; Epstein, Arthur J. | Effect of solvent on the magnetic properties of the high-temperature V[TCNE]x molecule-based magnet | The different magnetic behaviors of the V[TCNE]x (TCNE=tetracyanoethylene) magnet prepared via the reaction of TCNE and V(CO)6 in CH2Cl2 and the solvent-free chemical vapor deposition (CVD) of TCNE and V(CO)6 onto a glass substrate were determined. It was shown that the presence of noncoordinating C... | Magnetization; Molecule | 2001 |
197 |
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Stang, Peter J. | Studies in the cycloproparene series: cycloaddition reactions of diarylmethylidenecycloproparenes | Diarylmethylidenecyclopropanaphthalenes 4b-d add diphenylisobenzofuran (DPIBF) and α-pyrone across the exocyclic double bond to give ring expanded products 11b-d and 13b-d that result from subsequent relief of ring strain in the non-isolable spirocyclic intermediates 10 and 12, respectively. The be... | Cycloproparene series; Cycloaddition; Diarylmethylidenecycloproparenes; Ab initio calculations; Strained aromatics; Acetylenic-iodonium salts; Crystal structures; Cyclobutanes, Diels-Alder cycloaddition; norcaradienes | 2001 |
198 |
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Morse, Michael David | Dispersed fluorsecence spectroscopy of jet-cooled AgAu and Pt? | Dispersed fluorescence spectroscopy has been used to study jet-cooled AgAu and Pt2 . Fluorescence resulting from the excitation of five bands of the A?X 1?+ system of AgAu was dispersed, and 51 measured ground state vibrational levels were fit to provide ground state vibrational constants of ?"e=198... | | 2001 |
199 |
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Miller, Joel Steven | Structure, optical and magnetic behaviour of meso-tetraphenyl-porphyrinatoiron(III) tetracyanoethenide, [FeIII(TPP)]+[TCNE].-* | The direct redox reaction between tetracyanoethylene (TCNE) and meso-tetraphenylporphyrinatoiron(II), [FeII(TPP)], formed the electron transfer salt (ETS) [FeIII(TPP)][TCNE], which has been structurally, spectroscopically, and magnetically characterized. It has an extended one-dimensional linear ch... | Magnets; Spin; Electron | 2001 |
200 |
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Truong, Thanh | Branching ratio and pressure dependent rate constants of multichannel unimolecular decomposition of gas-phase ?-HMX: an ab initio dynamics study | The dynamics of the initial thermal decomposition step of gas-phase ?-HMX is investigated using the master equation method. Both the NO2 fission and HONO elimination channels were considered. The structures, energies, and Hessian information along the minimum energy paths (MEP) of these two channels... | Thermal decomposition; HMX | 2001 |