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201 - 225 of 322
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CreatorTitleDescriptionSubjectDate
201 Miller, Joel StevenPotential technology directions of molecular metalsIn the past decade, anisotropic molecular conductors have been found which possess unusual electrical, optical, magnetic, and in some cases mechanical properties. Exploiting these properties for specific devices is inevitable, and a number of diverse applications of molecular metals have been repor...Molecular metals1979
202 Poulter, Charles DalePredicting the functions and specificity of triterpenoid synthases: a mechanism-based multi-intermediate docking approachTerpenoid synthases construct the carbon skeletons of tens of thousands of natural products. To predict functions and specificity of triterpenoid synthases, a mechanism-based, multi-intermediate docking approach is proposed. In addition to enzyme function prediction, other potential applications of ...2014-01-01
203 Morse, Michael DavidPredissociation lifetimes of vibrational levels of the excited ? B? (Ka=O) electronic states of Cd ? H? and Cd ? D? complexesThe experimental rates of predissociation of vibrational levels of the ?B? (K'a-O) excited states of the Cd ? HZ and Cd ? D2 complexes are shown to be consistent with both semiclassical and quantum-mechanical pseudodiatomic theoretical treatments of the process. The ?B? pseudodiatomic potential was ...1992
204 Poulter, Charles DalePrenyltransferase. Kinetic studies of the 1'-4 coupling reaction with avian liver enzyme.Prenyltransferase catalyzes the sequential, irreversible 1'-4 condensation of isopentenyl-PP with dimethylallyl-PP and geranyl-PP to yield farnesyl-PP. A kinetic study shows substrate inhibition by isopentenyl-PP at concentrations above 0.7 microM when the concentration of geranyl-PP is 1.0 microM o...Birds; Kinetics; Structure-Activity Relationship; Substrate Specificity1979-10-10
205 Miller, Joel StevenPreparation and characterization of square-planar tetrakis(cyanoacetylide) complexes: [MII(C=C-C=N)4]2- (M = Ni,Pd, Pt)Complexes [MII(C=C-=N)4]2 - (M = Ni, Pd, Pt) are prepared for the first time and the structure of [NEt4]2[Ni(C=C-C=N)4] is determined to have a square-planar geometryBonding; Structure; Ligand1996
206 Miller, Joel StevenPressure dependence of magnetic ordering temperature for decamethylferrocenium tetracyanoethenideIt has been demonstrated that the linear-chain charge-transfer salt, decamethylferrocenium tetracyanoethanide (DMeFc) (TCNE), is a ferromagnet with a transition temperature of -4.8 K. This low-temperature 3D ordering has been attributed to a strong intrachain and a weak interchain interaction. To...Ferromagnetic; Transition; Antiferromagnetic1993
207 Miller, Joel StevenPressure-induced phase transition in a molecule-based magnet with interpenetrating sublatticesThe molecule-based magnet [Ru2(O2CMe)4]3[Cr(CN)6] contains two interpenetrating sublattices with sublattice moments confined to the cubic diagonals. At ambient pressure, a field of about 850 Oe rotates the antiferromagnetically coupled sublattice moments toward the field direction, producing a wasp...2010-05
208 Armentrout, Peter B.Probes of spin conservation in heavy metal reactions: experimental and theoretical studies of the reactions of Re+ with H2, D2, and HDA guided ion beam tandem mass spectrometer is used to examine the kinetic energy dependence of reactions of the third-row transition metal cation, Re1, with molecular hydrogen and its isotopologues. A flow tube ion source produces Re1 in its 7S3 electronic ground state.Endothermic reactions; Transition metal ions; Rhenium ions; Dihydrogen2004
209 Miller, Joel Steven; Epstein, Arthur J.Proton spin-lattice and spin-spin relaxation times of (N(CH3)3)H)(I)(TCNQ)Proton spin-lattice T(1) and spin-spin T(2) relaxation times are reported for (N(CH(3))(3)H)(I)(TCNQ) in the temperature range 150 to 5OOK. The overall relaxation process of the system can be described by contributions from rotation of the N(CH3)3H+ group about its symmetry axis, tumbling of that g...Transition; Reorientation; Conductivity1978
210 Poulter, Charles DalePurification and characterization of farnesyl diphosphate/geranylgeranyl diphosphate synthaseFarnesyl diphosphate (FPP)/geranylgeranyl diphosphate (GGPP) synthase, a bifunctional enzyme that synthesizes C15 and C2o isoprenoid diphosphates from isopentenyl diphosphate and dimethylallyl diphosphate, was purified to homogeneity from the archae-bacterium Methanobacterium thermoautotrophicum. Th...Bifunctional enzyme; Methanobacterium thermautotrophicum; Synthases1993-05-25
211 Voth, Gregory AlanQuantitative assessment of the accuracy of centroid molecular dynamics for the calculation of the infrared spectrum of liquid waterA detailed analysis of the infrared lineshapes corresponding to the intramolecular bond vibrations of HOD in either H2O or D2O is presented here in order to quantitatively assess the accuracy of centroid molecular dynamics in reproducing the correct features of the infrared spectrum of water at amb...2010
212 Truong, Thanh; Sarofim, Adel F.Quantum mechanic study of high molecular mass compounds in combustion conditionsExperimental 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 formation2001
213 Miller, Joel Steven; Epstein, Arthur J.Quest for a polymeric ferromagnet: a new polymorph of 1,4-bis(2,2,6,6-tetramethyl-4-oxy-4-piperidyl-1-oxy)butadiyne (invited)A new polymorph of 1,4-bis(2,2,6,6-tetramethyl-4-oxy-4-piperidyl-l-oxy) butadiyne has been prepared and characterized by x-ray diffraction, infrared and Raman spectroscopies, and magnetic susceptibility. Unlike t h e Pccn-a phase, the B phase belongs to the Pca2y1 space group [a = 14.265(1) A(o),b ...Molecular; Magnetic; Thermal1988
214 Miller, Joel Steven; Epstein, Arthur J.Quest for molecule-based magnetsIn the past decade a new class of magnets possessing spins on organic species have been discovered and studied. These magnets can be fabricated at room temperature and may enable useful devices and/or processes. Herein we discuss several of the mechanisms that can enable the stabilization of magn...Mechanisms; Ferromagnetic; Spin coupling1996
215 Truong, ThanhReaction class transition state theory: hydrogen abstraction reactions by hydrogen atoms as test casesWe 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; Hydrogen2000
216 Armentrout, Peter B.Reaction of Cr+, Mn+, Fe+, Co+, and Ni+ with O2 and N2O. Examination of the translational energy dependence of the cross sections of endothermic reactionsReactions of Cr+, Mn+, Fe+, Co+, and Ni+ with 02 and N20 to yield metal oxide ions are examined using an ion beam apparatus. Reaction cross sections a as a function of ion translational energy E are reported. With one exception, Fe+ + N20, the cross sections exhibit an energy threshold E0.Metal oxides; Endothermic reactions; Translational energy; Bond energy; Threshold energy1982
217 Armentrout, Peter B.Reaction of Cu+ with dimethoxyethane: competition between association and multiple dissociation channelsThe reaction of Cu1 with dimethoxyethane (DXE) is studied using kinetic-energy dependent guided ion beam mass spectrometry. The bimolecular reaction forms an associative Cu1(DXE) complex that is long-lived and dissociates into several competitive channels: C4H9O2 11CuH, Cu1(C3H6O)1CH3OH, back to rea...Dimethoxyethane; Copper ions; Association reactions; Collision-induced dissociation; Phase state theory2004
218 Armentrout, Peter B.Reactions of Ar+, Ne+, and He+ with SiF4 from thermal energy to 50 eV c.m.Guided ion-beam techniques are used to measure the cross sections for reaction of SiF4 with Ar+, Ne+, and He+ from thermal to 50 eV. Charge transfer followed by loss of F atoms are the sole processes observed. All SiFx + (x = 0-4) products are observed, except for SiF4 + from reaction with Ne+ and ...Ion-molecule reactions; Tetrafluorosilane; Rare gas ions; Endothermic reactions; Plasma systems1989
219 Armentrout, Peter B.Reactions of Pt+ with H2, D2, and HD: effect of lanthanide contraction on reactivity and thermochemistryA guided ion beam tandem mass spectrometer is used to examine the kinetic energy dependence of reactions of the third-row transition metal cation, Pt1, with molecular hydrogen and its isotopologs. A flow tube ion source produces Pt1 ions in its electronic ground state term and primarily in the lowes...Metal clusters; Platinum ions; Lanthanide contraction; Bond energies; Endothermic reactions; Transition metal ions; Dihydrogen2002
220 Armentrout, Peter B.Reactions of Ta+ and W+ with H2, D2, and HD: effect of lanthanide contraction and spin-orbit interactions on reactivity and thermochemistryA guided ion beam tandem mass spectrometer is used to examine the kinetic energy dependence of reactions of the third-row transition metal cations, Ta1, and W1, with molecular hydrogen and its isotopologs. A flow tube ion source produces Ta1 and W1 ions in their electronic ground state term and p...Metal clusters; Tantalum ions; Tungsten ions; Lanthanide contraction; Bond energies; Endothermic reactions; Transition metal ions; Dihydrogen2002
221 Armentrout, Peter B.Reactions of Ta+, W+, and Pt+ with H2, D2, and HD: effect of lanthanide contraction and spin-orbit interactions on reactivity and thermochemistryThere have been extensive experimental studies of the reactions of atomic first-row and second-row transition metal cations with dihydrogen and its isotopic analogues in our group. For third-row transition metal cations, however, only La+ and Lu+ systems have been studied experimentally although t...Lanthanide contraction; Spin-Orbit interactions; Reactivity2002
222 Miller, Joel Steven; Epstein, Arthur J.; Zhang, JieReentrance in the Mn(tetracyanoethylene)x.y(CH2Cl2) high-Tc molecule-based ferrimagnetResults of static and dynamic magnetic studies of the compound Mn(TCNE)x•y(CH2Cl2) (TCNE =tetracyanoethylene) are reported. Curie-Weiss analysis of the high-temperature susceptibility data indicates a relatively strong exchange. The ac susceptibility, measured as a function of frequency and tempe...Transition; Reentrant; Magnetic1998
223 Armentrout, Peter B.Relative and absolute bond dissociation energies of sodium cation-alcohol complexes determined using competitive collision-induced dissociation experimentsAbsolute (R1OH)Na+-(R2OH) and relative Na+-(ROH) bond dissociation energies are determined experimentally by competitive collision-induced dissociation of (R1OH)Na+(R2OH) complexes with xenon in a guided ion beam mass spectrometer. The alcohols examined include ethanol, 1-propanol, 2-propanol, n-but...2010
224 Morse, Michael DavidResonant two-photon ionization spectroscopy of BNBTriatomic BNB has been produced by laser ablation of a boron nitride rod in a supersonic expansion of helium carrier gas and has been investigated using resonant two-photon ionization spectroscopy in the visible region. The B? 2IIg?X? 2?u + band system has been recorded near 514 nm and is dominated ...2006
225 Morse, Michael DavidResonant two-photon ionization spectroscopy of coinage metal trimers: Cu?Ag, Cu?Au, and CuAgAuThe jet-cooled coinage metal triatomic molecules Cu, Ag, Cu, Au, and CuAgAu have been investigated using resonant two-photon ionization spectroscopy. One band system, labeled as the ?-x system, has been observed for each species, with origin bands at 13 188, 17 217, and 17 470 cm -?, respectively. ...1991
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