Search results for "spin [neutron star]"
showing 10 items of 813 documents
Synthesis, Crystal Structures, and Magnetic Properties of a New Family of Heterometallic Cyanide-Bridged FeIII2MII2 (M = Mn, Ni, and Co) Square Compl…
2011
New heterobimetallic tetranuclear complexes of formula [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Mn(II)(bpy)(2)](2)(ClO(4))(2)·CH(3)CN (1), [Fe(III){HB(pz)(3)}(CN)(2)(μ-CN)Ni(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (2a), [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Ni(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (2b), [Fe(III){HB(pz)(3)}(CN)(2)(μ-CN)Co(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (3a), and [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Co(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (3b), [HB(pz)(3)(-) = hydrotris(1-pyrazolyl)borate, B(Pz)(4)(-) = tetrakis(1-pyrazolyl)borate, dmphen = 2,9-dimethyl-1,10-phenanthroline, bpy = 2,2'-bipyridine] have been synthesized and structurally and magnetically characterized. Complexes 1-3b have be…
Pulsed EPR determination of water accessibility to spin-labeled amino acid residues in LHCIIb.
2009
Membrane proteins reside in a structured environment in which some of their residues are accessible to water, some are in contact with alkyl chains of lipid molecules, and some are buried in the protein. Water accessibility of residues may change during folding or function-related structural dynamics. Several techniques based on the combination of pulsed electron paramagnetic resonance (EPR) with site-directed spin labeling can be used to quantify such water accessibility. Accessibility parameters for different residues in major plant light-harvesting complex IIb are determined by electron spin echo envelope modulation spectroscopy in the presence of deuterated water, deuterium contrast in …
Spin-Crossover Modification through Selective CO2 Sorption
2013
[EN] We present a spin-crossover Fe-II coordination polymer with no permanent channels that selectively sorbs CO2 over N-2. The one-dimensional chains display internal voids of similar to 9 angstrom diameter, each being capable to accept one molecule of CO2 at 1 bar and 273 K. X-ray diffraction provides direct structural evidence of the location of the gas molecules and reveals the formation of O=C=O(delta(-))center dot center dot center dot pi interactions. This physisorption modifies the spin transition, producing a 9 K increase in T-1/2.
Single-Crystal X-Ray Diffraction Study of Pressure and Temperature-Induced Spin Trapping in a Bistable Iron(II) Hofmann Framework.
2020
High-pressure single-crystal X-ray diffraction has been used to trap both the low-spin (LS) and high-spin (HS) states of the iron(II) Hofmann spin crossover framework, [FeII (pdm)(H2 O)[Ag(CN)2 ]2 ⋅H2 O, under identical experimental conditions, allowing the structural changes arising from the spin-transition to be deconvoluted from previously reported thermal effects.
X-ray study of the light-induced metastable state of a spin-crossover compound
2000
Iron(II) complexes exhibiting thermal spin crossover may be converted from the1A1low-spin (LS) state to the5T2high-spin (HS) state by irradiation with green light (light-induced excited spin-state trapping, LIESST). The lifetime of the metastable LIESST state may be sufficiently long for X-ray diffraction study. The lattice parameters of a single crystal of [Fe(ptz)6](BF4)2(ptz = propyltetrazole) were measured between 300 and 10 K, while the crystal changed from the HS to the LS state near 135 K. Using the green light (514 nm) of an argon-ion laser, the crystal was quantitatively converted to the metastable LIESST state at 10 K; its lattice parameters were measured up to 50 K, at which poin…
EFFECT OF A FLUCTUATING ELECTRIC FIELD ON ELECTRON SPIN DEPHASING TIME IN III–V SEMICONDUCTORS
2012
We investigate the electron spin dephasing in low n-doped GaAs semiconductor bulks driven by a correlated fluctuating electric field. The electron dynamics is simulated by a Monte Carlo procedure which keeps into account all the possible scattering phenomena of the hot electrons in the medium and includes the evolution of spin polarization. Spin relaxation times are computed through the D’yakonov–Perel process, which is the only relevant relaxation mechanism in zinc-blende semiconductors. The decay of initial spin polarization of conduction electrons is calculated for different values of field strength, noise intensity and noise correlation time. For values of noise correlation time compara…
ESR Spectra o f Normal Human Serum after Treatment with Complement Activating Agents*
1980
Abstract We describe the appearance of a free-radical signal in the ESR spectrum of normal human serum incubated with several complement activating agents. The intensity of this signal is dependent of dose of activating agents, time and temperature. Signals elicited by different complement activators differ in morphology and kinetics. Inhibition by treatment with EDTA and the presence of the signal in activated C 6-deficient rabbit serum suggest that the con-vertase forming steps of complement activation (C2 to 5) could be the source of free-radical containing molecules.
NUCLEAR MAGNETIC ORDER, USE OF SPIN DEPENDENT AMPLITUDES
1993
The use of the spin dependent part of the nuclear scattering length gives access to neutron scattering to the field of nuclear magnetism. This paper presents the theoretical and experimental background for such experiments. The available results on nuclear order will be reviewed and put if possible in the larger frame of many body physics. The possibilities of using nuclear magnetism for new applications or the improvement of scattering techniques will be stressed as well.
Dark-matter detection by elastic and inelastic LSP scattering on 129Xe and 131Xe
2008
Abstract We calculate the nuclear matrix elements involved in the elastic and inelastic scattering of the lightest supersymmetric particle (LSP) on the 129Xe and 131Xe dark-matter detector nuclei. This is the first time when both channels are addressed within the same unified microscopic nuclear framework, namely we perform large-scale shell-model calculations with a realistic two-body interaction to produce the participant nuclear wave functions. These wave functions successfully reproduce the spectroscopic data on the relevant magnetic moments and M1 decays. The tested wave functions are used to produce annual average detection rates for both the elastic and inelastic channels. It is foun…
First Example of Coexistence of Thermal Spin Transition and Liquid-Crystal Properties.
2001
The rodlike FeIII complex of an N-alkyloxysalicylidenyl-N'-ethyl-N-ethylenediamine ligand, shown as a computer model in the picture, is the first compound in which spin-crossover (SC) and liquid-crystalline (LC) properties coexist. This synergy should allow the magnetic and optical properties of SC compounds to be combined with the sensitivity of the LC state to electromagnetic fields.