UScholar Works
 
Filters: Department: "Chemistry" Collection: "ir_uspace" Format: "application/pdf"
101 - 125 of 322
Number of results to display per page
CreatorTitleDescriptionSubjectDate
101 Miller, Joel Steven; Epstein, Arthur J.Optical control of magnetic order in molecule-based magnet Mn(TCNE)x.y(CH2Cl2)Studies of photoinduced magnetization and photoinduced absorption in molecule-based magnet Mn(TCNE)x•y(CH2Cl2) (x=2, y-0.8, TCNE=tetracyanoethylene) are reported. Optical excitation in the blue region of spectrum leads to increased magnetization, accompanied by changes in the electronic spectrum...Spectrum; Absorption; Illumination2002
102 Morse, Michael DavidLaser vaporization generation of Y ??B+, Y ??B+, and YAI+ for electron spin resonance studies in neon matrices at 4 K: comparison with theoretical calculationsThe first spectroscopic investigation of 89Y 10B+, 89Y 11B+, and 89Y 27Al+ is reported, revealing that both of these diatomic cation radicals have X 4?- electronic ground states. The ions were generated by three high energy techniques in combination with neon matrix isolation at 4 K and studied by e...1992
103 Miller, Joel StevenMnII(TCNE)3/2(I3)1/2-A 3D network-structured organic-based magnet and comparison to a 2-D analogOrganic-based magnets utilize unpaired electrons residing on organic species to form magnetically ordered materials. Unlike traditional atom/ion-based magnets, they enable the controllable modulation and combination of magnetic properties with other technologically important properties (e.g., electr...2010
104 Morse, Michael DavidSpectroscopy and electronic structure of jet-cooled NiPd and PdPtResonant two-photon ionization spectroscopy of jet-cooled NiPd and PdPt has revealed a dense vibronic spectrum for NiPd and a much more sparse spectrum for PdPt. Four vibrational progressions have been identified for NiPd, and three have been located for PdPt. High resolution investigations of NiPd...1990
105 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
106 Armentrout, Peter B.Mechanism of proton exchange: guided ion beam studies of the reactions, H(H2O)n+ (n=1-4) + D2O and D(D 2O)n+ (n=1-4) + H2OReactions of protonated water clusters, H(H2O)n+ (n=1-4) with D2O and their "mirror" reactions, D(D2O)n+ (n=1-4) with H2O, are are studied using guided-ion beam mass spectrometry. Absolute reaction cross sections are determined as a function of collision energy from thermal energy to over 10 eV.Collision-induced dissociation; Proton exchange; Protonated water clusters; Exothermic reactions; Deuterium oxide2004
107 Morse, Michael DavidSpectroscopy of mixed early-late transition metal diatomics: ScNi, YPd, and ZrCoResonant 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
108 Miller, Joel Steven[Cyanil]2 2- dimers possess long, two-electron ten-center (2e-/10c) multicenter bondingA long, two-electron ten-center (2e-/10c) [8 carbon plus 2 oxygen] bond in diamagnetic dimers of radical-anion tetracyano-1,4-benzoquinoneide (cyanil, [Q]2 2-, is described by B2LYP and CASSCF92,2)/MCQDPT calculations.Carbon bonds; Cyanil2008
109 Morse, Michael DavidSpectrsocopy of Jet-cooled YCuOptical 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
110 Miller, Joel Steven; Epstein, Arthur J.Optical properties of quinolinium tetracyanoquinodimethanide, [Qn(TCNQ)2] and (N-methylphenazinium)x(phenazine)1-x (tetracyanoquinodimethane) [(NMP)x(Phen)1-x(TCNQ)]We present here optical-absorption data of quinolinium ditetracyanoquinodimethanide [Qn(TCNQ)2] and (N-methylphenazinium)x(phenazine)1-x(tetracyanoquinodimethanide) [(NMP)x(Phen)1-x(TCNQ)] for 0.5 <_x<_ 0.6. These materials span the range of electronic structure from commensurate, to commensurate ...Commensurate; Lattice; Electron1989
111 Morse, Michael DavidLaser excitation spectroscopy of the A and B states of jet-cooled copper dimer: evidence for large electronic isotope shiftsFluorescence excitation spectra recorded for the A-X system of jet-cooled Cu2 show conclusive evidence of a ?? = 0 transition, and the A state is thereby definitively assigned as ??u+. A previous assignment of the B state as ??u+ is confirmed, but the vibrational levels of this state are complicated...1989
112 Miller, Joel StevenStructural and magnetic characterization of a- and B-2,4-hexadiyne-1,6-diyl Bis(2,2,5,5-tetramethyl-1-oxyl-3-pyrroline-3-carboxylate) and its thermal degradation productThe search for ferromagnetic organic compounds and polymers is the focus of contemporary research.1 - 5 Polymerization of di-iminoxyl diacetylene monomers has been suggested as a means to prepare a high spin potentially ferromagnetically coupled polymers3 and the thermal, photochemical, and glow di...Ferromagnetic; Magnetization; Polymers1989
113 Armentrout, Peter B.Guided ion beam study of collision-induced dissociation dynamics: integral and differential cross sectionsThe low energy collision-induced dissociation (CID) of Cr(CO)6+ with Xe is investigated using a recently modified guided ion beam tandem mass spectrometer, in the energy range from 0 to 5 eV in the center-of-mass (CM) frame. The additions to the instrument, updated with a double octopole system, and...Collision-induced dissociation; Bond energies; Chromium carbonyl; Xenon2001
114 Morse, Michael DavidSpectroscopic studies of jet-cooled AINiResonant two-photon ionization spectroscopy has been used to interrogate diatomic AlNi produced by laser vaporization of a 1:l alloy target in a supersonic molecular beam of helium. Although a large density of states in this molecule prohibits a concise elucidation of its electronic structure, the p...1993
115 Miller, Joel Steven1H NMR investigation of the magnetic spin configuration in the molecule-based ferrimagnet [MnTFPP][TCNE]1H NMR line-shape measurements have been performed in the linear chain molecule-based ferrimagnet [MnTFPP][TCNE].xPhMe (TFPP=tetrakis(4-fluorophenyl)porphinato; TCNE=tetracyanoethylene) as a function of temperature. Hyperfine shifts of opposite sign were observed indicating the presence of two oppo...Magnetization; Magnets; Paramagnetic2002
116 Morse, Michael DavidElectronic structure of the 4d transition metal carbides: dispersed fluorescence spectroscopy of MoC, RuC, and PdCDispersed fluorescence studies of the diatomic molecules MoC, RuC, and PdC are reported. New states identified in MoC and RuC are the [...]2?112?1, 3,1?2 states and the [...]2? 312?1, 1?2 state, respectively. Five states re observed by dispersed fluorescence in PdC. The ground state is found to be [...2001
117 Miller, Joel StevenStructure and magnetic properties of MnII[N(CN)2]2(pyrazine). An antiferromagnet with an interpenetrating 3-D network structureMn[N(CN)2]2(pyz) (pyz = pyrazine) orders antiferromagnetically at low temperature and possesses intralayer u-NCNCN and interlayer u-pyz ligands that form a pseudo-ReO3 interpenetrating network structure.Dicyanamide; Polydentate; Temperature1998
118 Miller, Joel StevenStructure and magnetic properties of meso-tetrakis(2,4,6-trimethylphenyl)porphyrinatomanganese(III) 7,7,8,8-tetracyano 2,5-dimethyl-p-quinodimethanide with a 2.3 K Tc. The first example of cis-coordination of a tetracyano-p-quinodimethanideThe crystal structure of meso-tetrakis(2,4,6-trimethylphenyl)porphyrinatomanganese(III) 7,7,8,8-tetracyano-2,5-dimethyl-p-quinodimethanide, [MnTMesP][DMTCNQ]-2p-C6H4Me2 provides the first example of a cis-1,2-u-coordination motif having an infinite zigzag chain structure. [MnTMesP][DMTCNQ]-2p-C6H4Me...Magnets; Interactions; Coupling2000
119 Miller, Joel Steven[Et4N]2[TCNE]2 (TCNE = tetracyanoethylene) - an example of an exceptionally long 2.827 Ã CC bondInterest in organic compounds exhibiting unusually long CC bonds has been the subject of several recent studies.1-3 The longest sp3-sp3 C-C single bond reported to date is 1.73 A°,1,2 whereas several [TCNE]22- (TCNE = tetracyanoethylene) dimers have been recently reported to form cation-assisted, l...Synthesis; Crystal; Solution2001
120 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
121 Miller, Joel Steven; Epstein, Arthur J.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
122 Morse, Michael DavidSpectrosopic studies of jet-cooled NiAu and PtCuSpectroscopic investigations of NiAu and PtCu have revealed that both molecules possess 2?5/2 ground electronic states, and are in this respect analogous to the isovalent molecule NiCu. The ground-state bond lengths (r?) have been measured as 2.351?0.001 ? and 2.335?0.001 ? for NiAu and PtCu, respe...1992
123 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
124 Morse, Michael DavidRotationally resolved spectra of jet-cooled RuSiWe report the first gas-phase spectroscopic investigation of diatomic ruthenium silicide (RuSi). The molecules were produced by laser ablation of a Ru disk into a flow of helium carrier gas containing 0.5% SiH4, and were cooled in a supersonic expansion. The RuSi molecules were then studied using re...2007
125 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
101 - 125 of 322