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76 Armentrout, Peter B.Energy dependence, kinetic isotope effects, and thermochemistry of the nearly thermoneutral reactions of N+(3P) + H2(HD, D2) → NH+(ND+) + H(D)The reactions of N + (3P) ions with H2 , HD, D2 are examined using guided ion beam tandem mass spectroscopy. Absolute reaction cross sections are measured from near thermal energies to 30 eV relative energy. The low energy cross section behavior is analyzed using empirical threshold models and ph...Thermoneutral reactions; Ion-molecule reactions; Translational energy; Bond energy; Threshold behavior; Phase space theory1987
77 Poulter, Charles DaleEnzymes encoded by the farnesyl diphosphate synthase gene family in the big sagebrush Artemisia tridentata ssp. spiciformisFarnesyl diphosphate synthase catalyzes the sequential head-to-tail condensation of two molecules of isopentenyl diphosphate with dimethylallyl diphosphate. In plants the presence of farnesyl diphosphate synthase isozymes offers the possibility of differential regulation. Three full-length cDNAs enc...Amino Acid Sequence; Base Sequence; Molecular Sequence Data2003-08-22
78 Miller, Joel Steven; Epstein, Arthur J.Evidence for solitons in conducting organic charge-transfer crystalsMagnetic susceptibility of (N-methylphenazinium)x(phenazine)(1-x (tetracyanoquinodimethanide) [(NMP)x(Phen)1-x(TCNQ)] shows the formation of defect states for 0.5<x<0.54. Diffuse x-ray scattering and g-value studies indicate that these defects are solitons formed in the highly correlated quasi-one-...TCNQ; X-ray scattering1982
79 Miller, Joel StevenFar-infrared powder spectrum of (N(CH3)3D)(I)(TCNQ)We present the powder absorption spectrum of (TMA)(I)(TCNQ) in the far-infrared as a function of temperature. Below 160 K new absorption features appear and others increase in intensity. This behaviour supports the electron- neutron-diffraction evidence of a distortion on the TCNQ chains below the f...Conductivity, Crystals, Electrons1983
80 Miller, Joel StevenFar-infrared properties of trimethylammonium iodide tetracyanoquinodimethaneWe present the powder absorption spectrum of (TMA) (I)(TCNQ) in the far-infrared as a function of temperature. Below 16 K new absorption features appear and others increase in intensity. This behaviour supports the electron and neutron diffraction evidence of a distortion on the TCNQ chains below...Trimethylammonium iodide tetracyanoquinodimethane; TCNQ1983
81 Poulter, Charles DaleFarnesyl diphosphate synthetase: molecular cloning, sequence, and expression of an essential gene from Saccharomyces cerevisiaeFarnesyl diphosphate (FPP) synthetase is a key enzyme in isoprenoid biosynthesis which supplies C15 precursors for several classes of essential metabolites including sterols, dolichols, and ubiquinones. The structural gene for FPP synthetase was isolated on a 4.5-kilobase EcoRI genomic restriction f...Genetics; Transferases; Dimethylallyltranstransferase/biosynthesis1989-11-15
82 Poulter, Charles DaleFarnesyl pyrophosphate synthetase. Mechanistic studies of the 1'-4 coupling reaction with 2-fluorogeranyl pyrophosphate.The mechanism of the 1'-4 coupling reaction between isopentenyl pyrophosphate and geranyl pyrophosphate catalyzed by farnesyl pyrophosphate synthetase from porcine liver was studied with the allylic substrate analogue 2-fluorogeranyl pyrophosphate. 2-Fluorogeranyl pyrophosphate is an alternate subst...Kinetics; Liver; Mass Spectrometry; Organophosphorus Compounds; Protein Binding1978-10-25
83 Miller, Joel StevenFerrimagnetic ordering of a methylthio-substituted planar porphyrin based electron transfer salt, octakis(2,3,7,8,12,13,17,18-methylthio)porphyrinatomanganese(III) tetracyanoethanideThe 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; Coupling2000
84 Miller, Joel StevenFerrimagnetic 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; Magnetic2001
85 Miller, Joel Steven; Epstein, Arthur J.Ferrimagnetic resonance in films of vanadium [tetracyanoethanide]x, grown by chemical vapor depositionFerrimagnetic resonance (FMR) measurements in thin films of V[TCNE]x grown by chemical vapor deposition exhibit a series of sharp lines at 300 K. The orientational dependence of these lines is a result of the sample geometry provided the magnetization tracks the applied magnetic field. The FMR inten...Spin; Anisotropy; Magnetization2004
86 Miller, Joel Steven; Epstein, Arthur J.Ferromagnetic behavior and magnetic excitations in a molecular-based alternating-spin chain: decamethylchromocenium tetracyanoethenideWe report the study of magnetic properties of a molecular-based alternating-spin chain: metallocenium electron-transfer salt decamethylchromocenium tetracyanoethanide, [CrCp(*2)] [TCNE]. We give a modified spin-wave theory for the Heisenberg alternating-spin chains. The low-field susceptibility and...TCNE; Magnetization1994
87 Miller, Joel Steven; Epstein, Arthur J.Ferromagnetic behavior of decamethylchromocenium tetracyanoethenide, [CrCp*2][TCNE]Studies on the magnetic properties of decamethylchromocenium tetracyanoethanide, [CrCp*2][TCNE] are reported herein. Near-zero field (H= 150 mG) data indicates a ferromagnetic transition with T(c)=3.65 K. The temperature dependence below T(c) can be fit to a mean-field result M=M(o)(1 - T(o))(1/2)...Magnetic; Magnetization; Transition1993
88 Miller, Joel Steven; Epstein, Arthur J.Ferromagnetic properties of one-dimensional decamethylferrocenium tetracyanoethylenide (1:1): [Fe(n5-C5Me5)2].+[TCNE].-[Fe(C5Me5)2].+ [TCNE].-- has been characterized by magnetic susceptibility to possess dominant ferromagnetic interactions; its structure has been determined by X-ray crystallography.Susceptibility; Crystal; Magnetic1986
89 Miller, Joel Steven; Epstein, Arthur J.Ferromagnetism in molecular decamethylferrocenium tetracyanoethylenide: (DMeFc TCNE)The temperature and magnetic field dependence of the magnetization and susceptibility of single-crystal decamethylferrocenium tetracyanoethenide demonstrate that this material is the first molecular compound with a ferromagnetic ground state. A spontaneous magnetization is observed for T < 4.8 K. T...Magnetization; Ferromagnetic1987
90 Miller, Joel Steven; Epstein, Arthur J.Ferromagnetism in molecular materials: decamethylferrocenium tetracyanoethanide [DMeFc][TCNE] (invited)Ferromagnetism has only recently been observed in molecular materials. We present here a summary of the ferromagnetic phenomena observed in the molecular charge transfer salt, decamethylferrocenium tetracyanoethanide (DMeFc) (TCNE), and related compounds. A spontaneous magnetization is observed i...Magnetic; Magnetization1988
91 Armentrout, Peter B.Fifty years of ion and neutral thermochemistry by mass spectrometryOriginating with the appearance potentials for "positive rays", the ability of mass spectrometry to obtain quantitative information about the energetics of both ions and neutrals has evolved dramatically. About 50 years ago, many of the techniques that are now common place were first implemented, th...2014-01-01
92 Morse, Michael DavidFirst spectroscopic investigation of the 4 d transition metal monocarbide MoCThe first optical spectroscopic investigation of MoC has revealed a complicated vibronic spectrum consisting of about 35 bands between 17 700 and 24 000 cm-1. Analysis has shown the ground state to be the ?=0+ spin?orbit component of a 3?- state that derives from a 10?211?25rr42d 2 configuration. Th...1998
93 Miller, Joel StevenFormation of a zwitterionic donor-acceptor compound based on N,N,N',N'-tetramethly-p-phenylenediamine and 7,7,8,8-tetracyanoperfluoro-p-quinodimethaneThe reaction of the donor N,N,N',N'- tetramethyl-p-phenylenediamine (TMPD) with the acceptor 7,7,8,8-tetracyanoperfluoro-p-quinodimethane (TCNQF4) has led to the isolation of a novel type of zwitterionic donor-acceptor compound whose structure has been determined by X-ray crystallography.Ccrystals; Single bond1988
94 Miller, Joel StevenFormation of Ni[C4(CN)8] from the reaction of Ni(COD)2 (COD = 1,5-cyclooctadiene) with TCNE in THFThe dissolution of Ni(COD)2 (COD = 1,5-cyclooctadiene) into dichloromethane leads to decomposition and formation of a room temperature magnetic material, whereas the reaction of Ni(COD)2 and tetracyanoethylene (TCNE) in THF forms paramagnetic materials including NiII[C4(CN)8](THF)2.xTHF. These resu...Dinuclear complexes2007
95 Miller, Joel Steven; Epstein, Arthur J.Forthcoming attractionsMagnets made from molecules and ions having spins in p orbitals have only been discovered in the past decade. Their solubility in organic solvents and room temperature manufacture means that they should find a variety of applications.Electron; Temperature; Magnets1994
96 Armentrout, Peter B.Fragmentation reactions of thiourea- and urea-compounds examined by tandem MS-, energy-resolved CID experiments, and theoryFragmentation reactions of thiourea- and urea-compounds, which are promising reagents for chemical crosslinking (XL), are investigated in detail by collision-induced dissociation (CID) experiments in a quadrupole ion trap (QIT), energy-resolved CID experiments, and computational modeling. For this s...2012-01-01
97 Voth, Gregory AlanFurther developments in the local-orbital density-functional-theory tight-binding methodQuantum-mechanical methods have become increasingly reliable as a complementary tool to experimental research. A variety of methods exist ranging in complexity from semiempirical methods to density-functional-theory (DFT) methods [using either the local-density approximation (LDA) or the generalize...Sankey-Niklewaki method; Fireball method; Pseudopotential; Exchange-correlation interactions; Gallium nitride; H20 dimer; Copper; gas-phase HMX2001-10
98 Morse, Michael DavidThe ground state and excited ?-hole states of CuAuResonant two-photon ionization spectroscopy has been applied to jet-cooled diatomic CuAu. Eight band systems have been observed, rotationally resolved, and analyzed. The ground state is X??+ in symmetry, deriving from the 3d??Cu 5d??Au, ?? molecular configuration. Its bond length has been determined...1991
99 Armentrout, Peter B.Guided ion beam and theoretical studies of sequential bond energies of water to sodium cysteine cationAbsolute 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
100 Armentrout, Peter B.Guided ion beam and theoretical studies of the reaction of Ag+ with CS2: gas-phase thermochemistry of AgS+ and AgCS+ and insight into spin-forbidden reactionsThe gas-phase reactivity of the atomic transition metal cation, Ag+, with CS2 is investigated using guided-ion beam mass spectrometry. Endothermic reactions forming AgS+ and AgCS+ are observed but are quite inefficient. This observation is largely attributed to the stability of the closed shell Ag+(...2010
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