UScholar Works
 
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1 Miller, Joel Steven; Epstein, Arthur J.Viscous behavior in a quasi-1D fractal cluster glassThe spin glass transition of a quasi-1D organic-based magnet ([MnTPP][TCNE]) is explored using both ac and dc measurements. A scaling analysis of the ac susceptibility shows a spin glass transition near 4 K, with a viscous decay of the thermoremanent magnetization recorded above 4 K.We propose an ex...Transition; Magnet; Magnetization2002
2 Miller, Joel Steven; Epstein, Arthur J.Magnetic properties and critical behavior of Fe(tetracyanoethylene) 2.x(CH2Cl2): a high-Tc molecule-based magnetWe report magnetic studies of Fe(TCNE)2•x(CH2Cl2), a member of the family of high-Tc molecule-based magnets, M(TCNE)x•y (solvent) (M=V, Mn, TCNE=tetracyanoethelyne). Based on extensive static and dynamic magnetic measurements we show that this system has a complex magnetic behavior, with a mixtu...Solvent; Anisotropy; Spin2000
3 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
4 Blumenthal, Donald K.; Trewhella, JillConformationally dynamic C helix of the RIalpha subunit of protein kinase A mediates isoform-specific domain reorganization upon C subunit binding.Different isoforms of the full-length protein kinase A (PKA) regulatory subunit homodimer (R2) and the catalytic (C) subunit-bound holoenzyme (R2C2) have very different global structures despite similar molecular weights and domain organization within their primary sequences. To date, it has been th...Protein Isoforms; Global Structures; cAMP2005-10-21
5 Miller, Joel Steven; Epstein, Arthur J.Anomalous relaxation in a quasi-one-dimensional fractal cluster glassThe low-temperature spin glass state of the quasi-1D organic-based magnet [MnTPP]+[TCNE]- .x(1,3-C6H4Cl2) has unusually long relaxation times due to frustration induced by dipole-dipole interactions between fractal spin clusters. This long relaxation is investigated with in-field relaxation measurem...Sweep rate; Bifurcation; Magnetization2004
6 Armentrout, Peter B.Kinetic energy dependence of Al+ + O2→AlO+ + OThe endothermic reaction of Al+ with O2 is studied using a guided ion-beam apparatus. The reaction cross section is measured as a function of kinetic energy from 0 to 20 eV. The threshold energy for the reaction, E0, is determined from an empirical model to be 3.64 ± 0.04 eV.Ion-molecule reactions; Translational energy; Threshold behavior; Endothermic reactions; Aluminum; Oxygen1986
7 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
8 Armentrout, Peter B.Threshold behavior of endothermic reactions: C+(2P) + H2 → CH+ + HThe reaction C+(2p) + H2 → CH+ + H (1) and its deuterium analog is a model system in ion-molecule chemistry. It is of interest due to its astrophysical significance, because it is an endothermic process, and because the interaction involves several potential energy surfaces. Experimental work ha...Endothermic reactions; Translational energy; Threshold behavior1984
9 Miller, Joel Steven; Epstein, Arthur J.Magnetic phase diagram of a molecule-based ferrimagnet: weak ferromagnetism and multiple dimensionality crossoversA detailed study of the magnetic behavior of the molecule-based magnet, [MnOEP][HCBD], (OEP=mesooctaethylporphyrinato, HCBD=hexacyanobutadiene) from 1.7 to 20 K was performed. The earlier reported magnetic transition at 19.6 K, ascribed to a crossover from a one-dimensional Heisenberg-like ferrimag...Transition; Temperature; Magnetization1997
10 Truong, ThanhDirect ab initio dynamics studies of N + H2<-->NH + H reactionKinetics 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 constants2000
11 Miller, Joel Steven; Epstein, Arthur J.Local structural order in the disordered vanadium tetracyanoethylene room-temperature molecule-based magnetWe determined the vanadium oxidation state and local coordination environment in disordered samples of magnetic V[TCNE]x(x=2) prepared by chemical vapor deposition (CVD). Systematic studies of the x-ray absorption near-edge structure (XANES) in this material and reference compounds show that V ions ...Magnetic; Solvent; Structure2004
12 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
13 Poulter, Charles DaleTetartohedral twinning in IDI-2 from Thermus thermophilus: crystallization under anaerobic conditionsType-2 isopentenyl diphosphate isomerase (IDI-2) is a key flavoprotein involved in the biosynthesis of isoprenoids. Since fully reduced flavin mononucleotide (FMNH2) is needed for activity, it was decided to crystallize the enzyme under anaerobic conditions in order to understand how this reduced co...2014-01-01
14 Miller, Joel StevenMagnetic behaviors of the metamagnetic and ferromagnetic phases of [Fe(C5Me5)2][TCNQ] (TCNQ = 7,7,8,8-tetracyano-p-quinodimethane). Determination of the phase diagram for the metamagnetic phaseThe detailed magnetic behaviors of the ferro- (1FO) and metamagnetic (1MM) phases of [FeCp*2][TCNE] (Cp* = pentamethylcyclopentadienide; TCNE = tetracyanoethylene) aligned parallel to the applied magnetic field, H, were obtained using eicosane (E). The Tc for 1FO is 3.1 K from the maximum in the fr...Properties; Temperature; Ordering2006
15 Wight, Charles AlbertThermal dissociation kinetics of solid and liquid ammonium nitrateThermogravimetry 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 kinetics2001
16 Armentrout, Peter B.Translational energy dependence of O+(4S) + N2 → NO+ + N from thermal energies to 30 eV c.m.Guided ion beam mass spectrometry is used to examine the kinetic energy dependence of the reaction of ground state atomic oxygen ion with molecular nitrogen. An 0 + (4S) source which produces less than 0.06% excited states is described. Cross sections for the NO+ + N product channel decrease with...Ion-molecule reactions; Translational energy; Threshold behavior; Endothermic reactions; Nitrogen; Oxygen1987
17 Armentrout, Peter B.Effect of kinetic and electronic energy on the reactions of Mn+ with H2, HD and D2Reactions of several electronic states of Mn+ with H2, HD, and D2 have been examined using guided ion beam mass spectroscopy. The excitation function for the ground state of Mn+ ( 75) has two regions: one of very low reactivity at threshold and another more efficient pathway at higher energies. In ...Ion-molecule reactions; Translational energy; Bond energy; Threshold behavior; Endothermic reactions; Metal ions; Manganese; Hydrogen1986
18 Armentrout, Peter B.Alkali metal cation interactions with 12-crown-4 in the gas phase: revisitedQuantitative 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
19 Miller, Joel Steven; Epstein, Arthur J.Magnetization and dynamics of reentrant ferrimagnetic spin-glass [MnTPP]::+[TCNE].-.2PhMeWe present direct current (dc) magnetization M(T,H) and alternating current (ac) susceptibility Xac(T,H,f) data for the quasi-one-dimensional molecule-based ferrimagnet [MnTPP]::+[TCNE].-.•2PhMe (TPP=meso-tetraphenylporphyrinato, TCNE=tetracyanoethylene). Static scaling of the real part X' of ...Ferrimagnetic order; Magnetism1996
20 Miller, Joel StevenDimetallic complexes derived from a novel dinucleating chelating symmetric triazole ligand; crystal strcutrue,magnetic properties and ESR study of Bis[μ-3,5-diacetlyamino-1,2,4-triazolato-O',N1,N2,O"]bis[nitrato)(aqua)-copper(II)]Reaction of 3,5-diacetylamino-1,2,4-triazole (Hdaat) with copper(II), nickel(II) and cobalt(II) salts yields dinuclear co-ordination compounds, which were spectroscopically characterized. The crystal and molecular structure of one of the compounds, bis[u-3,5-diacetylamino-1,2,4-triazolato-0'_x0001_,...Susceptibility; Orbitals; Compounds1999
21 Miller, Joel StevenIsomeric conformations in a pentaco-ordinated ruthenium compound: crystal and molecular structures of the orange and violet isomers of (Ph3P)2[(CF3)2C2S2]Ru(CO)Summary The molecular conformations of two square pyramidal species, one violet the other orange, both composition (Ph3P)2[(CF3)2C2S2]Ru(CO) are described.Pyramidal, Radiation,1973
22 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
23 Wight, Charles AlbertKinetics of thermal decomposition of cubic ammonium perchlorateThe 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 calorimetry1999
24 Truong, ThanhThermal rate constants of the NO2 fission reaction of gas phase ?-HMX: a direct ab initio dynamics studyThe 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 theory2000
25 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
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