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Creator | Title | Description | Subject | Date |
101 |
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Miller, Joel Steven; Epstein, Arthur J. | Spin frustration and metamagnetic behavior in a molecular-based quasi 1-D-ferrimagnetic chain: (MnTPP)(TCNE) | We report an experimental observation of spin frustration and metamagnetic behavior in a quasi-1D ferrimagnetic chain, (MnTPP) + (TCNE) -. Metastability, hysteresis effects, and irreversibility of thermal and magnetic histories are observed in magnetization measurements. The "memory" phenomenon is ... | Magnetic; Magnetization; Anisotropy | 1993 |
102 |
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Miller, Joel Steven | Magnetization and static scaling of high-Tc disordered molecular-based magnet V(tetracyanoethylene)x¢y(CH3CN) with x ~ 1.5 and y ~ 2) | We report field (H) and temperature (T) -dependent magnetization (M) of a member of the new class of high-Tc molecular-based magnets V(tetracyanoethylene)x .y(solvent) with Tc in an accessible range (solvent =CH3CN). The M (H) at low T saturates slowly with increasing H. The random magnetic anisotro... | Temperature; Magnetic; Random | 1993 |
103 |
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Morse, Michael David | Photodissociation measurements of bond dissociation energies: Ti?+, V?+, Co?+, and Co?+ | The bond dissociation energies of Ti2+, V+2 , Co+2, and Co: have been measured from the sudden onset of predissociation in the photodissociation spectra of these molecules, yielding values of D?(Ti+2)=2.435+0.002 eV, D?(V+2)=3.140?0.002 eV, D?(Co+2)=2.7651?0.001 eV, and D?(Co+3)=2.086?0.002 eV. Thes... | | 1993 |
104 |
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Morse, Michael David | Laser vaporization generation of the SiB and SiAi radicals for matrix isolation electron spin resonance studies: comparison with theoretical calculations and assignment of their electronic ground states as X ?? | The first experimental spectroscopic study of the SiB and SiAl diatomic radicals is reported. Electron spin resonance results indicate that both molecules have X 4? ground electronic states, in agreement with earlier theoretical calculations. The SIB and SiAl radicals were generated in neon matrices... | | 1993 |
105 |
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Miller, Joel Steven | Pressure dependence of magnetic ordering temperature for decamethylferrocenium tetracyanoethenide | It 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; Antiferromagnetic | 1993 |
106 |
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Poulter, Charles Dale | Yeast squalene synthase. A mechanism for addition of substrates and activation by NADPH | Squalene synthase catalyzes the condensation of two molecules of farnesyl diphosphate (FPP) to give presqualene diphosphate (PSPP) and the subsequent reductive rearrangement of PSPP to squalene. Previous studies of the mechanism of addition of FPP to the enzyme have led to conflicting interpretation... | Enzyme Activation; Sesquiterpenes; Kinetics | 1993-04-15 |
107 |
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Poulter, Charles Dale | Purification and characterization of farnesyl diphosphate/geranylgeranyl diphosphate synthase | Farnesyl 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; Synthases | 1993-05-25 |
108 |
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Poulter, Charles Dale | (S)-Geranylgeranylglyceryl phosphate synthase. Purification and characterization of the first pathway-specific enzyme in archaebacterial membrane lipid biosynthesis | The first pathway-specific step in the biosynthesis of the core membrane diether lipids in archaebacteria is the alkylation of the primary hydroxyl group in (S)-glyceryl phosphate by geranylgeranyl diphosphate. The reaction is catalyzed by (S)-3-O-geranylgeranylglyceryl phosphate ((S)-GGGP) synthase... | Polyacrylamide gel; Molecular weight | 1993-10-15 |
109 |
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Miller, Joel Steven; Epstein, Arthur J. | Forthcoming attractions | Magnets 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; Magnets | 1994 |
110 |
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Poulter, Charles Dale | Isoprenyl diphosphate synthases: protein sequence comparisons, a phylogenetic tree, and predictions of secondary structure | Isoprenyl diphosphate synthases are ubiquitous enzymes that catalyze the basic chain-elongation reaction in the isoprene biosynthetic pathway. Pairwise sequence comparisons were made for 6 farnesyl diphosphate synthases, 6 geranylgeranyl diphosphate synthases, and a hexaprenyl diphosphate synthase... | Catalytic site; Evolution; Farnesyl diphosphate; Geranylgeranyl diphosphate; Prenyltransferase; Substrate binding: | 1994 |
111 |
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Morse, Michael David | Spectroscopy of mixed early-late transition metal diatomics: ScNi, YPd, and ZrCo | Resonant two-photon ionization spectroscopy has been employed to investigate the spectra of the jet-cooled transition metal diatomics ScNi, YPd, and ZrCo, which are isovalent species which possess ~or are thought to possess! an X 2?+ ground state. Several electronic band systems have been observed f... | | 1994 |
112 |
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Morse, Michael David | Interaction of an aluminum atom with a closed subshell metal atom: spectroscopic analysis of AIZn | Resonant two-photon ionization spectroscopy has been employed to investigate diatomic AlZn produced by laser vaporization of a 1:2 Al:Zn alloy target disk in a supersonic expansion of helium. Several discrete transitions are reported in the energy range from 18 400 to 19 100 cm-?. Most of these are... | | 1994 |
113 |
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Morse, Michael David | Interaction of an aluminum atom with an alkaline earth atom: spectroscopic and ab initio investigations of AICa | A spectroscopic analysis of diatomic AlCa generated by laser vaporization of a 2:1 AI:Ca metal alloy followed by supersonic expansion has been completed using resonant two-photon ionization spectroscopy. Four excited electronic states have been identified and investigated in the energy region from 1... | | 1994 |
114 |
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Miller, Joel Steven; Epstein, Arthur J. | Ferromagnetic behavior and magnetic excitations in a molecular-based alternating-spin chain: decamethylchromocenium tetracyanoethenide | We 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; Magnetization | 1994 |
115 |
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Miller, Joel Steven; Epstein, Arthur J. | Molecular magnets V(tetracyanoethylene)x.y(solvent): applications to magnetic shielding | The specific advantages and limitations of a new class of polymer based magnets [exemplified by V(TCNE)x. y (solvent) (TCNE= tetracyanoethylene)] for static and low frequency magnetic shielding and inductive applications are evaluated using results of dc superconducting quantum interference device ... | Frequency; Permeability; Transition | 1994 |
116 |
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Morse, Michael David | Ni? revisited: reassignment of the ground electronic state | Resonant two-photon ionization spectroscopy was used to study jet-cooled Ni2 produced by pulsed laser ablation of a nickel target in the throat of a supersonic nozzle using argon as the carrier gas. Spectral regions previously investigated using helium as the carrier gas were reinvestigated, and the... | | 1994 |
117 |
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Morse, Michael David | Spectroscopic analysis of the open 3 d subshell transition metal aluminides: AIV, AICr, and AICo | Three open 3d subshell transition metal aluminides, AlV, AICr, and AlCo, have been investigated by resonant two-photon ionization spectroscopy to elucidate the chemical bonding in these diatomic molecules. The open nature of the 3d subshell results in a vast number of excited electronic states in th... | | 1994 |
118 |
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Miller, Joel Steven | Isolation and structural determination of {(1,1,2,2-tetracyano-1,2-ethanediyl)bis[imino(cyanomethylene)]}bis-(cyanamide) ion(2--), [C12N12]2--, a new cyanocarbon | The oxidative degradation of [N(PPh3)2]3[Mnilll(CN)6] leads to the isolation of the unprecedented [C12N12]2- dianion, which is characterized by single-crystal X-ray diffraction and spectroscopic techniques. | Cyanogen; Bond; Absorptions | 1995 |
119 |
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Morse, Michael David | Spectrsocopy of Jet-cooled YCu | Optical spectra of jet-cooled diatomic YCu have been recorded using resonant two-photon ionization spectroscopy in a supersonic expansion of helium. The ground state is shown experimentally to be of 1?+ symmetry, with a measured bond length of re"=2.6197(6) ? and a vibrational frequency of 193.21(24... | | 1995 |
120 |
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Morse, Michael David | Ultraviolet photoelectron spectroscopy of molybdenum and molybdenum monoxide anions | The 351 nm photoelectron spectra of Mo-and MoO- have been measured. The electron affinity of atomic molybdenum is 0.748(2) eV and that of molybdenum monoxide is 1.290(6) eV. The term energies of several MoO electronic states not previously observed are obtained and compared with ab initio prediction... | | 1995 |
121 |
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Miller, Joel Steven; Epstein, Arthur J. | Magnetic behavior of octaethylporphyrinatomanganese(III) tetracyanoethenide, [MnOEP][TCNE], and hexacyanobutadienide, [MnOEP][C4(CN)6]: the importance of a uniform chain for stabilizing strong effective ferromagnetic coupling | [MnOEP][A] {A=[TCNE]'- and [C4(CN)6]'-} have been isolated as extended 1D coordination polymers with trans-U2"[A] bridging ligands with strong {A=[C4(CN)6].-} and weak {A=TCNE].-} ferromagnetic coupling as evidenced from the fit of the magnetic susceptibility to the Curie-Weiss law (0=5.1 and 67.1 K... | Crystals; Inversion; Coupling | 1995 |
122 |
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Poulter, Charles Dale | Isolation of Schizosaccharomyces pombe isopentenyl diphosphate isomerase cDNA clones by complementation and synthesis of the enzyme in Escherichia coli | Isopentenyl diphosphate (IPP) isomerase catalyzes an essential activation step in the isoprene biosynthetic pathway. The Saccharomyces cerevisiae gene for IPP isomerase, IDI1, was recently isolated and characterized (Anderson, M. S., Muehlbacher, M., Street, I. P., Proffitt, J., and Poulter, C. D. (... | Carbon-Carbon; Biosynthesis; Genetics | 1995-05-12 |
123 |
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Poulter, Charles Dale; Jiang, Yunfeng | BTS1 encodes a geranylgeranyl diphosphate synthase in Saccharomyces cerevisiae | Protein prenylation utilizes different types of isoprenoids groups, namely farnesyl and geranylgeranyl, to modify proteins. These lipophilic moieties attach to carboxyl-terminal cysteine residues to promote the association of soluble proteins to membranes. Most prenylated proteins are geranylgeranyl... | Amino Acid Sequence; Cloning, Molecular; Gene Expression | 1995-09-15 |
124 |
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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 |
125 |
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Miller, Joel Steven; Epstein, Arthur J. | Quest for molecule-based magnets | In 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 coupling | 1996 |