Search results for "SPIN STATES"
showing 10 items of 253 documents
Light-induced formation of metastable high-spin states in [Fe(mtz)6](CiO4)2
1988
[Fe(mtz)6](CiO4)2 (mtz=1-methyltetrazole) is a spin crossover compound with two different iron(II) lattice sites. Only one of them (lattice site A) shows thermally induced high spin (HS) ⇌ low spin (LS) spin transition. The LIESST effect (Light-Induced Excited Spin State Trapping) can be observed below 50 K. Complex molecules in B-sites remain in HS state at all temperatures. At ∼ 20 K irradiation with red light causes a partial conversion to another HS species, HS(C), with also practically infinite lifetime.
Spin transition in iron complexes induced by heat, pressure, light and nuclear decay
1988
The phenomenon of temperature-dependent spin transition will be introduced and the numerous chemical and physical influences affecting the spin transition characteristics will be discussed. We shall mainly concentrate on the spin crossover system [Fe(2-pic)3]X2·Sol (2-pic=2-aminomethylpyridine; X=Cl, Br; Sol=C2H5OH, CH3OH) and demonstrate how the behaviour of the spin transition5T2g(Oh)⇌1A1g(Oh) is influenced by substituting the metalion, the non-coordinating anions X, the crystal solvent molecules Sol and by isotopic exchange with H/D and14N/15N. It will also be shown that the spin transition is very susceptible to pressure. A quantitative spin state conversion from low spin to high spin c…
Determination of methemoglobin in human blood after ionising radiation by EPR
2015
In the present work presents results of investigations of radiation influence on blood of patients examined by radio-isotopes diagnosis (Tc 99m ), blood of Chernobyl clean-up workers and human blood irradiated by LINAC using Electron Paramagnetic Resonance (EPR). The EPR spectroscopy reveals information on electronic states of transition metal ions, particularly Fe 3+ in different spin states. It is shown that EPR spectra of blood of patients before examination has signal from metal-protein transferrin (g=4.3) and after administration of radio- isotope proves signal of Fe 3+ (methemaglobin) in the high spin state (g=6.0). The EPR spectra of Chernobyl liquidator display number of signals inc…
Discovery of New Fission Product Activities in the A=110–118 Mass Region
1986
Neutron rich nuclei around the mass A=100 have recently attracted both theoretical and experimental interest since they are expected to form a new region of strong deformation. In contrary, very little experimental information is available in the adjacent transitional region A= 110–118. Due to expected isomerism in this region both low and high spin states can be studied via beta decay in many nuclei. The studies of these nuclides have many experimental difficulties. They are only weakly produced in thermal neutron induced fission and because all the elements in this mass region (Tc, Ru, Rh, Pd) have very high melting points they have not been available as beams of on-line isotope separator…
New Features in the Systematics of Low‐Spin States in Even 106‐120Cd
1991
Low‐spin states in even 106‐112Cd and 116Cd were investigated by in‐beam and off‐beam γ‐ray and conversion‐electron spectroscopy. New spin assignments and decay branching ratios for the levels in 106Cd,108Cd,110Cd and 112Cd were obtained. From the new systematical data for the even 106‐120Cd, it is inferred that two sets of low‐lying 0+ states cross between 114Cd and 116Cd. One of these sets appears to have features of both intruder and two‐quadrupole‐phonon states.
Anomalous Behavior of High-Spin States inCm248
1981
The ground-state band of $^{248}\mathrm{Cm}$ has been studied up to spin ${28}^{+}$ and tentatively to ${30}^{+}$ by observing $\ensuremath{\gamma}$ rays following multiple Coulomb excitation with use of $^{208}\mathrm{Pb}$ ions at 5.3 MeV/u. A smooth, gradual increase in the effective moment of inertia is seen at lower spin with an anomalous forward bend above spin ${22}^{+}$. Calculations are presented which indicate that this behavior including the forward bend can be understood in terms of the alignment of single-particle angular momenta along the rotation axis.
Systematic study of low-spin states in even Cd nuclei.
1992
Low-lying low-spin collective states in even $^{106\mathrm{\ensuremath{-}}112}\mathrm{Cd}$ and $^{116}\mathrm{Cd}$ were investigated using in-beam and off-beam \ensuremath{\gamma}-ray and conversion-electron spectroscopy. New spin assignments and decay branching ratios for the levels in $^{106}\mathrm{Cd}$, $^{108}\mathrm{Cd}$, $^{110}\mathrm{Cd}$, and $^{112}\mathrm{Cd}$ were obtained. The present results essentially complement the level systematics from $^{106}\mathrm{Cd}$ to $^{120}\mathrm{Cd}$. From the new data, it is inferred that two sets of low-lying ${0}^{+}$ states having different excitation characteristics cross between $^{114}\mathrm{Cd}$ and $^{116}\mathrm{Cd}$. No correspondi…
Shape isomerism and spectroscopy ofHg177
2003
High spin states in the $^{177}\mathrm{Hg}$ nucleus were populated by the $^{144}\mathrm{Sm}(^{36}\mathrm{Ar},3\mathrm{n})^{177}\mathrm{Hg}$ reaction at a beam energy of $178\phantom{\rule{0.3em}{0ex}}\text{MeV}$. The emitted prompt $\ensuremath{\gamma}$ rays were detected with the Jurosphere $\ensuremath{\gamma}$-ray spectrometer, while the recoiling nuclei were identified using an active stopper at the focal plane of the gas-filled separator RITU. A quasi-rotational band that decays to an isomeric state with a half-life ${t}_{1∕2}=1.50\ifmmode\pm\else\textpm\fi{}0.15\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ and its subsequent $\ensuremath{\gamma}$ decay to the ground state of…
Interaction between heterobinuclear molecules and nature of the ground spin state in oximato-bridged [CuIIMII]2 bis-binuclear complexes (M=Cu, Ni, Mn…
1999
[EN] Two new heterobimetallic complexes [Cu(pdmg)Ni(Me-3[12]N-3)(CH3CH2OH)](ClO4)(2)(2) and [Cu(pdmg) Mn(bipy)(2)]-ClO4)(2) . H2O (3) (H(2)pdmg = 3,9-dimethyl-4,8-diazaundeca-3,8-diene-2 10-dione dioxime; Me-3[12]N-3 = 2,4,4-trimethyl-1,5,9-triazacyclododeca-1-ene; bipy = 2,2'-bipyridyl) have been prepared and characterized. The structure of 2 has been determined by single-crystal X-ray diffraction methods. It consists of [Cu(pdmg)Ni(Me-3[12]N-3)(CH3CH2OH)](2+) cations and non-coordinated perchlorate anions. The [Cu(pdmg)(CH3CH2OH)] complex coordinates to the [Ni(Me-3[12]N-3)](2+) fragment to afford the binuclear unit doubly-bridged by oximato groups in cis arrangement. The coordination geo…
Bidirectional photo-switching of the spin state of iron(II) ions in a triazol based spin crossover complex within the thermal hysteresis loop
2009
Abstract We have investigated the effect of short laser pulses (532 nm, 4 ns, −2 ) on the spin state of iron(II) ions in the spin crossover compound {[Fe II (Htrz) 2 (trz)](BF 4 )} within the hysteresis region of the high-spin (HS) to low-spin (LS) first-order thermal phase transition. Using Raman spectroscopy we have evidenced quasi-complete HS → LS as well as LS → HS photo-conversions, which can be induced by a single laser shot in the descending (351 K) and ascending (378 K) branches of the hysteresis loop, respectively. No effect has been observed, however, close to the center of the hysteresis loop even for repeated exposures.