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Creator | Title | Description | Subject | Date |
26 |
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Armentrout, Peter B. | Infrared multiple photon dissociation spectroscopy of protonated histidine and 4-phenyl imidazole | The gas-phase structures of protonated histidine (His) and the side-chain model, protonated 4-phenyl imidazole (PhIm), are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy utilizing light generated by the free electron laser FELIX. To identify the structures present in t... | | 2012-01-01 |
27 |
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Armentrout, Peter B. | The simplest b2+ ion: determining its structure from its energetics by a direct comparison of the threshold collision-induced dissociation of protonated oxazolone and diketopiperazine | Energy-resolved collision-induced dissociation of b2 + ions derived from protonated GGG and GAG are compared with that of protonated diketopiperazine (H+DKP). Absolute dissociation cross sections are obtained using a guided ion beam tandem mass spectrometer and analyzed using statistical methods. Th... | | 2012-01-01 |
28 |
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Armentrout, Peter B. | Thermodynamics and mechanisms of protonated diglycine decomposition: a computational study | We present a full computational description of the fragmentation reactions of protonated diglycine (H+GG). Relaxed potential energy surface scans performed at B3LYP/6-31G(d) or B3LYP/6-311+G(d,p) levels are used to map the reaction coordinate surfaces and identify the transition states (TSs) and int... | | 2012-01-01 |
29 |
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Armentrout, Peter B. | Thermodynamics and mechanisms of protonated diglycine decomposition: a guided ion beam study | We present a full molecular description of fragmentation reactions of protonated diglycine (H+GG) by studying their collision-induced dissociation (CID) with Xe using a guided ion beam tandem mass spectrometer (GIBMS). Analysis of the kinetic energy-dependent CID cross sections provides the 0 K barr... | | 2012-01-01 |
30 |
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Armentrout, Peter B. | Alkali metal cation interactions with 12-crown-4 in the gas phase: revisited | Quantitative interactions of alkali metal cations with the cyclic 12-crown-4 polyether ligand (12C4) are studied. Experimentally, Rb+(12C4) and Cs+(12C4) complexes are formed using electrospray ionization and their bond dissociation energies (BDEs) determined using threshold collision-induced dissoc... | | 2012-01-01 |
31 |
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Armentrout, Peter B. | Role of methylation on the thermochemistry of alkali metal cation complexes of amino acids: N-methyl proline | Quantitative thermodynamic information is obtained from the study of the gasphase interactions of the alkali metal cation complexes of N-methyl proline (NMP) with Xe using a guided ion beam tandem mass spectrometer (GIBMS). Absolute bond dissociation energies (BDEs) of M+ = Li+, Na+, K+, and Rb+ to ... | | 2012-01-01 |
32 |
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Wight, Charles Albert | Kinetics of thermal decomposition of cubic ammonium perchlorate | The methods of thermogravimetric analysis (TGA) and differential scanning calorimettry (DSC) have been used to study the thermal decomposition of ammonium perchlorate (AP). TGA curves obtained under both isothermal and nonisothermal conditions show a characteristic slowdown at the extents of convers... | Thermal decomposition; Cubic ammonium perchlorate; Differential scanning calorimetry | 1999 |
33 |
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Truong, Thanh | High level ab initio and density functional theory evaluation of combustion reaction energetics: NO2 and HONO elimination from dimethylnitramine | Dimethylnitramine (DMNA) is used as a model system for investigating accurate and efficient electronic structure methods for nitramines. Critical points on the potential energy surfaces of DMNA, CH3NCH3, CH3NCH2, NO2, HONO, and the transition state to HONO elimination were located through geometry o... | Dimethylnitramine; DMNA; Nitramines; Combustion reaction energetics | 1999 |
34 |
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Wight, Charles Albert | Thermal dissociation kinetics of solid and liquid ammonium nitrate | Thermogravimetry has been used to study the kinetics of the thermal dissociation of solid and liquid ammonium nitrate. Model-fitting and model-free kinetic methods have been applied to the sets of isothermal and nonisothermal measurements to derive kinetic characteristics of the processes. The appli... | Thermal dissociation kinetics | 2001 |
35 |
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Wight, Charles Albert | Thermal decomposition of a melt-castable high explosive: isoconversional analysis of TNAZ | The thermal decomposition kinetics of the high explosive 1,3,3-trinitroazetidine (TNAZ) have been measured by nonisothermal differential scanning calorimetry (DSC). Samples of TNAZ in open pans and pierced pans undergo mainly melting (?Hfus = 27 ± 3 kJ mol-1) and vaporization (?Hvap = 74 ± 10 kJ m... | Thermal decomposition; Melt-castable high explosive; TNAZ; Nonisothermal differential scanning calorimetry; Exothermic decomposition | 2002 |
36 |
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Armentrout, Peter B. | Guided ion beam and theoretical studies of sequential bond energies of water to sodium cysteine cation | Absolute bond dissociation energies of water to sodium cysteine (Cys) cations and cysteine to hydrated sodium cations are determined experimentally by collision-induced dissociation of Na+Cys(H2O)x, where x = 1 - 4, complexes with xenon in a guided ion beam mass spectrometer. Experimental results sh... | | 2010-01-01 |
37 |
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Truong, Thanh | Direct ab initio dynamics studies of the hydrogen abstraction reactions of hydrogen atom with fluoromethanes | A direct ab initio dynamics study on the gas-phase reactions of atomic hydrogen with different fluoromethanes has been carried out. The thermal rate constants were calculated using canonical variational transition state (CVT) theory augmented by multidimensional semiclassical zero and small curvatur... | Hydrogen abstraction reactions; Gas-phase reactions; Fluoromethanes; Thermal rate constants; Moller?Plesset perturbation theory; Hybrid density functional theory | 1999 |
38 |
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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 |
39 |
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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 |
40 |
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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 |
41 |
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Truong, Thanh | Importance of polarization in simulations of condensed phased energetic materials | An embedded cluster model is used to estimate the molecular dipole moment of crystalline dimethylnitramine (DMNA). The electrostatic potential due to the crystal is included in the calculation via the SCREEP (surface charge representation of the electrostatic embedding potential) approach. The resul... | Dimethylnitramine; DMNA; Embedded cluster model | 1999 |
42 |
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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 |
43 |
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Voth, Gregory Alan | Systematic coarse-graining of nanoparticle interactions in molecular dynamics simulation | A recently developed multiscale coarse-graining procedure [Izvekov, S.; Voth, G. A. J. Phys. Chem. B 2005, 109, 2469] is extended to derive coarse-grained models for nanoparticles. The methodology is applied to C60 and to carbonaceous nanoparticles produced in combustion environments. The coarse-gra... | Systematic coarse-graining; Multiscale coarse-graining | 2005 |
44 |
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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 |
45 |
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Wight, Charles Albert | Thermal activation of the high explosive NTO: sublimation, decomposition, and autocatalysis | Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) show that the heating of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) leads to competitive sublimation and condensed-phase exothermic decomposition. Model-free isoconversional analysis has determined activation energies... | NTO; Thermal activation; Differential scanning calorimetry; Exothermic decomposition; Competitive sublimation | 2002 |
46 |
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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 |
47 |
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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 |
48 |
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Wight, Charles Albert | Kinetic study of stabilizing effect of oxygen on thermal degradation of poly(methyl methacrylate) | The thermal degradation of poly(methyl methacrylate) (PMMA) has been studied in both pure nitrogen and oxygen-containing atmospheres. The presence of oxygen increases the initial decomposition temperature by 70 °C. The stabilizing effect of oxygen may be explained by forming thermally stable radica... | Poly(methyl methacrylate); PMMA; Thermal degradation; Isoconversional method | 1999 |
49 |
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Armentrout, Peter B. | Guided ion beam and theoretical study of the reactions of Hf+ with H2, D2, and HD | The kinetic energy dependences of reactions of the third-row transition metal cation Hf+ with H2, D2, and HD were determined using a guided ion beam tandem mass spectrometer. A flow tube ion source produces Hf+ in its 2D (6s25d1) electronic ground state level. Corresponding state-specific reaction c... | | 2010-01-01 |
50 |
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Miller, Joel Steven | Decamethylnickelocenium hydrogen-7,7,8,8-tetracyanoperfluoro-p-quinodimethandiide: isolation of the protonated weak base [HTCNQF4]- | Unprecedently stable hydrogen-7,7,8,8- tetracyanoperfluoro-p-quinodimethandiide, [HTCNQF4]-, is isolated and crystallographically characterized. | Structure; Electron; Transfer | 1996 |