Spin transport of electrons and holes in a metal and in a
... Conventionally, the spin transport in a conductor is described by the model of spin-up/spin-down bands [1]. This model assumes that all electrons of an electron gas can be divided into two independent groups: a group of electrons with the spin-up spin projections and a group of electrons with the sp ...
... Conventionally, the spin transport in a conductor is described by the model of spin-up/spin-down bands [1]. This model assumes that all electrons of an electron gas can be divided into two independent groups: a group of electrons with the spin-up spin projections and a group of electrons with the sp ...
Photoelectron imaging spectroscopy of Cu (H2O)1,2
... of Cu, whose electron affinity (1.236 eV) is well established [24]. With appropriate adjustment of the photoelectron imaging optics, the energy resolution (DE) of the photoelectron spectrometer is measured to be 19 meV at 1.13 eV electron kinetic energy (eKE), with this image filling the detector. The ...
... of Cu, whose electron affinity (1.236 eV) is well established [24]. With appropriate adjustment of the photoelectron imaging optics, the energy resolution (DE) of the photoelectron spectrometer is measured to be 19 meV at 1.13 eV electron kinetic energy (eKE), with this image filling the detector. The ...
9 - MIT
... The Cytochrome P-450 Reaction Cycle When an axial site is available on the iron porphyrin, dioxygen can bind and/or be activated there. With protonmediated reductive activation of the O2 molecule, a peroxo intermediate forms that converts to an FeIV=O species, the ferryl ion. The ferryl can oxidize ...
... The Cytochrome P-450 Reaction Cycle When an axial site is available on the iron porphyrin, dioxygen can bind and/or be activated there. With protonmediated reductive activation of the O2 molecule, a peroxo intermediate forms that converts to an FeIV=O species, the ferryl ion. The ferryl can oxidize ...
feature article - Semantic Scholar
... molecules.11 Intermolecular complexes can be stabilized through weak dispersive forces, electrostatic effects (for example charge-charge, charge-dipole, and charge-induced dipole interactions) and donor-acceptor type orbital interactions such as forward and back-donation of electron density between ...
... molecules.11 Intermolecular complexes can be stabilized through weak dispersive forces, electrostatic effects (for example charge-charge, charge-dipole, and charge-induced dipole interactions) and donor-acceptor type orbital interactions such as forward and back-donation of electron density between ...
Lec 26 - An
... been applied to the determination of every metal cation. Thus, the reagent might appear at first glance to be totally lacking in selectivity. In fact, however, considerable control over interferences can be realized by pH regulation. For example, trivalent cations can usually be titrated without int ...
... been applied to the determination of every metal cation. Thus, the reagent might appear at first glance to be totally lacking in selectivity. In fact, however, considerable control over interferences can be realized by pH regulation. For example, trivalent cations can usually be titrated without int ...
Chapter One Hemilabile Ligands in Transition
... classical organic and inorganic chemistry because they look at the interaction between inorganic metal ions and organic molecules. Transition metal ions act as Lewis acids and can bind to Lewis bases known as ligands (L) to give a coordination compound, or complex MLn. The ligands bind in the first ...
... classical organic and inorganic chemistry because they look at the interaction between inorganic metal ions and organic molecules. Transition metal ions act as Lewis acids and can bind to Lewis bases known as ligands (L) to give a coordination compound, or complex MLn. The ligands bind in the first ...
Bonding in minerals - The Mineralogical Society of Great Britain and
... X-ray emission spectroscopy. The basic principles of an X-ray emission spectrometer, in which X-ray spectra including VXE spectra can be measured, are well known (see, for example, Compton and Allinson, 1935; Agarwal, 1979; or Jenkins and de Vries, 1970). X-ray emission, except for hard X-rays with ...
... X-ray emission spectroscopy. The basic principles of an X-ray emission spectrometer, in which X-ray spectra including VXE spectra can be measured, are well known (see, for example, Compton and Allinson, 1935; Agarwal, 1979; or Jenkins and de Vries, 1970). X-ray emission, except for hard X-rays with ...
Dimethylsulphoxide Complexes of Vanadium(III) o
... bonded to the metal ion. The peak at around 285 cm- I is assigned for the M-Q-S angle deformation as reported for the [Cr(DMSO)]," species (Berney and Weber 1968) and the bands at 275·205 cm- l region to CH 3 torsion modes. Although bands below 100 cm- 1 , assigned to coordinated DMSO have been repo ...
... bonded to the metal ion. The peak at around 285 cm- I is assigned for the M-Q-S angle deformation as reported for the [Cr(DMSO)]," species (Berney and Weber 1968) and the bands at 275·205 cm- l region to CH 3 torsion modes. Although bands below 100 cm- 1 , assigned to coordinated DMSO have been repo ...
Palladium Complexes Bearing Novel Strongly Bent Trans
... chloroform at room temperature, resulting in the formation of complexes 4 and 5 in 94 and 88% yields, respectively (Scheme 2). 31P{1H} NMR measurements indicated that the complexation of the palladium with the ligands was complete within 20-30 min at room temperature. The 31P{1H} NMR spectrum of com ...
... chloroform at room temperature, resulting in the formation of complexes 4 and 5 in 94 and 88% yields, respectively (Scheme 2). 31P{1H} NMR measurements indicated that the complexation of the palladium with the ligands was complete within 20-30 min at room temperature. The 31P{1H} NMR spectrum of com ...
11_chapter 1
... Most of the chelating resins come under this category. These are characterized by their relatively well defined co-ordination structure. Here the effect of the polymer chain is more predominant (Pittman et al 1971). ...
... Most of the chelating resins come under this category. These are characterized by their relatively well defined co-ordination structure. Here the effect of the polymer chain is more predominant (Pittman et al 1971). ...
New Insights into the Coordination Chemistry and Molecular
... In our opinion, a more successful strategy to gain more insight into the coordination chemistry of Cu2+/his complexes is to combine several complementary analytical techniques in one integrated approach, which allows analysis at more or less the same sample conditions. To our knowledge, such a multi ...
... In our opinion, a more successful strategy to gain more insight into the coordination chemistry of Cu2+/his complexes is to combine several complementary analytical techniques in one integrated approach, which allows analysis at more or less the same sample conditions. To our knowledge, such a multi ...
Effect of Alkali metal salt KCl Doping on Optical and
... comes from unsaturated bonds C=O and/or C=C present in the tail-head of PVA. The presence of dopant and its interaction results in the creation of new molecular dipoles could be a result of point defects created within the band gap. Using the observed UV-Vis spectra, the optical energy band gap Eg i ...
... comes from unsaturated bonds C=O and/or C=C present in the tail-head of PVA. The presence of dopant and its interaction results in the creation of new molecular dipoles could be a result of point defects created within the band gap. Using the observed UV-Vis spectra, the optical energy band gap Eg i ...
TRIPURA UNIVERSITY Syllabus For
... kinetic energy of molecules, mean free path, collision diameter, collision number, collision frequency, their dependence on temperature and pressure, heat capacity of gases, atomicity of molecule, viscosity of gases. ii) Real gases: Deviation from ideal behavior, Regault, Andrews and Amagat experime ...
... kinetic energy of molecules, mean free path, collision diameter, collision number, collision frequency, their dependence on temperature and pressure, heat capacity of gases, atomicity of molecule, viscosity of gases. ii) Real gases: Deviation from ideal behavior, Regault, Andrews and Amagat experime ...
Spin crossover
Spin Crossover (SCO), sometimes referred to as spin transition or spin equilibrium behavior, is a phenomenon that occurs in some metal complexes wherein the spin state of the complex changes due to external stimuli such as a variation of temperature, pressure, light irradiation or an influence of a magnetic field.With regard to a ligand field and ligand field theory, the change in spin state is a transition from a low spin (LS) ground state electron configuration to a high spin (HS) ground state electron configuration of the metal’s d atomic orbitals (AOs), or vice versa. The magnitude of the ligand field splitting along with the pairing energy of the complex determines whether it will have a LS or HS electron configuration. A LS state occurs because the ligand field splitting (Δ) is greater than the pairing energy of the complex (which is an unfavorable process).Figure 1 is a simplified illustration of the metal’s d orbital splitting in the presence of an octahedral ligand field. A large splitting between the t2g and eg AOs requires a substantial amount of energy for the electrons to overcome the energy gap (Δ) to comply with Hund’s Rule. Therefore, electrons will fill the lower energy t2g orbitals completely before populating the higher energy eg orbitals. Conversely, a HS state occurs with weaker ligand fields and smaller orbital splitting. In this case the energy required to populate the higher levels is substantially less than the pairing energy and the electrons fill the orbitals according to Hund’s Rule by populating the higher energy orbitals before pairing with electrons in the lower lying orbitals. An example of a metal ion that can exist in either a LS or HS state is Fe3+ in an octahedral ligand field. Depending on the ligands that are coordinated to this complex the Fe3+ can attain a LS or a HS state, as in Figure 1.Spin crossover refers to the transitions between high to low, or low to high, spin states. This phenomenon is commonly observed with some first row transition metal complexes with a d4 through d7 electron configuration in an octahedral ligand geometry. Spin transition curves are a common representation of SCO phenomenon with the most commonly observed types depicted in Figure 2 in which γHS (the high-spin molar fraction) is plotted vs. T. The figure shows a gradual spin transition (left), an abrupt transition with hysteresis (middle) and a two-step transition (right). For a transition to be considered gradual, it typically takes place over a large temperature range, even up to several hundred K, whereas for a transition to be considered abrupt, it should take place within 10 K or less.These curves indicate that a spin transition has occurred in a metal complex as temperature changed. The gradual transition curve is an indication that not all metal centers within the complex are undergoing the transition at the same temperature. The abrupt spin change with hysteresis indicates a strong cooperativity, or “communication”, between neighboring metal complexes. In the latter case, the material is bistable and can exist in the two different spin states with a different range of external stimuli (temperature in this case) for the two phenomena, namely LS → HS and HS → LS. The two-step transition is relatively rare but is observed, for example, with dinuclear SCO complexes for which the spin transition in one metal center renders the transition in the second metal center less favorable.There are several types of spin crossover that can occur in a complex; some of them are light induced excited state spin trapping (LIESST), ligand-driven light induced spin change (LD-LISC), and charge transfer induced spin transition (CTIST).