201 - 225 of 338
Number of results to display per page
CreatorTitleDescriptionSubjectDate
201 Optical spectroscopy of tungsten carbide (WC)Resonant two-photon ionization spectroscopy has been used to study the diatomic transition-metal carbide, WC. A low-resolution scan revealed a five-member vibrational progression beginning with the 0-0 band at 17 585 cm-1. Analysis of this progression yielded a vibrational frequency of ?'e8(184W12C)...2002
202 Organic and molecular ferromagnetsUnlike common ferromagnets such as iron, nickel, cobalt or even cobalt-samarium and Nb-Fe-B, it is extremely rare for a discrete molecule, especially an organic or polymeric material, to have cooperative magnetic interactions. Since the mid-1980s a few such materials have been prepared which demon...Magnetic; Magnetization; Temperature1992
203 Oxidation reactions at variably sized transition metal centers: Fen+ and Nbn+ + O2 (N=1-3)Cross sections for the reactions of Fen+ and Nbn+ (n = 1-3) with 02 are measured as a function of kinetic energy over a range of 0 to > 10 eV. In all systems, analysis yields insight into the kinetics and thermochemistry of the oxidation processes. Nbn+ reaction with 02 exothermically near the Lange...Metal clusters; Nobium ions; Iron ions; Exothermic reactions1989
204 Photobioelectrochemistry: Solar energy conversion and biofuel production with photosynthetic catalystsPhotobioelectrochemical cells are devices which have been developed over the past few decades and use photosynthetic catalysts for solar energy conversion or biofuel production. In this paper, a critical review of reported photobioelectrochemical systems is presented. The systems discussed include s...2014-01-01
205 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
206 Photoelectron spectra of transition-metal carbonyl complexes: comparison with the spectra of adsorbed COThe uv and x-ray photoelectron spectra of carbon monoxide and transition-metal (TM) carbonyl complexes have been studied. The systematic changes in these spectra were recorded as the number of metal atoms in the complexes was increased and as the bonding configuration of the CO changed. The observat...TM carbonyl complexes; electron binding energies; metal atoms1978
207 Photoelectron spectra of transition-metal carbonyl complexes: comparison with the spectra of adsorbed COThe uv and x-ray photoelectron spectra of carbon monoxide and transition-metal (TM) carbonyl complexes have been studied. The systematic changes in these spectra were recorded as the number of metal atoms in the complexes was increased and as the bonding configuration of the CO changed. The observat...TM carbonyl complexes; electron binding energies; metal atoms1978
208 Photoemission of ferrocene, decamethylferrocene, and decamethylferrocene-bis(7,7,8,8-tetracyano-p-quinodimethane)We present the first vacuum ultraviolet photoemission measurements of condensed ferrocene, decamethylferrocene, and the highly conductive charge transfer complex decamethylferrocene-7,7,8,8-tetracyano-p-quinodimethane, at photon energies from 7.7 to 21.2 eV. We compare the electronic spectra of thes...Energy; Transfer; TCNQ1977
209 Photoinduced magnetism, dynamics, and cluster glass behavior of a molecule-based magnetThe dynamic susceptibility study of photoinduced magnetism in a molecule-based magnet, (K1-2xCo1+x [Fe(CN)6]. yH2O (0.2<_x<_0.4,y-5), is reported. Upon excitation with visible light the material has substantial changes in linear and nonlinear ac susceptibility and dc magnetization. The results d...Magnetization; Light; Magnetometer2000
210 Photoinduced magnetization in the organic-based magnet Mn(TCNE)x.y(CH2Cl2)Photoinduced magnetization in a magnet based on organic species is reported for the first time. Upon optical excitation in the blue region of spectrum, Mn (tetracyanoethylene)x .y(CH2Cl2) (x=2,y-0.8) exhibits increased magnetic susceptibility at temperatures as high as 75 K, accompanied with photo-i...Absorption; Magnetic; Infrared2002
211 Photoreceptor cGMP phosphodiesterase delta subunit (PDEdelta) functions as a prenyl-binding proteinBovine PDEdelta was originally copurified with rod cGMP phosphodiesterase (PDE) and shown to interact with prenylated, carboxymethylated C-terminal Cys residues. Other studies showed that PDEdelta can interact with several small GTPases including Rab13, Ras, Rap, and Rho6, all of which are prenylate...Fluorescence Resonance Energy Transfer; GTP Phosphohydrolases; Immunohistochemistry2004
212 Potential 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
213 Predicting 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
214 Predissociation 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
215 Prenyltransferase. 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
216 Preparation 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
217 Pressure 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
218 Pressure-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
219 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
220 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
221 Purification 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
222 Quantitative 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
223 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
224 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
225 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
201 - 225 of 338