K-shell polarization of O ions in ferromagnets by spin dependent electron promotion via molecular orbitals

Transient field precessions of the 6.13 MeV¹⁶O(3^-) state have been measured in polarized Fe and Ni in order to corroborate our earlier results on C ions. It is found that precessions in Fe and Ni scale with the polarized electron density of the host at v_ion = 3.0 v₀ and are comparable at v_ion = 1.5 v₀. The latter is attributed to direct K-shell polarization of the ion by spin dependent electron promotion via molecular orbitals.     

The space-filling pentahedra

A space-filling polyhedron is one whose replications can be packed to fill three-space completely. There are only four space-filling tetrahedra. These and the known space-filling polyhedra of five faces are described and tabulated.     

Types In Sln

Let G = SL_n(F) where F is a non-Archimedean local field. Thispaper concerns the smooth (complex) representation theory ofG, specifically, the construction of types in G, in the senseof Bushnell and Kutzko. The main result describes a type foreach non-supercuspidal component of the Bernstein decompositionof G. If this is combined with earlier work of Bushnell andKutzko, it follows that G admits a complete set of types. 2000 Mathematical Subject Classification: 22E50.     

Canonical curves in P3

Let Hilb^6t–3(P³) be the Hilbert scheme of closed 1-dimensionalsubschemes of degree 6 and arithmetic genus 4 in P³. Let H bethe component of Hilb^6t–3(P³) whose generic point correspondsto a canonical curve, that is, a complete intersection of aquadric and a cubic surface in P³. Let F be the vector spaceof linear forms in the variables z₁, z₂, z₃, z₄. Denote by F_dthe vector space of homogeneous forms of degree d. Set X = (f₂,f₃)where f₂ P(F₂) is a quadric surface, and f₃ P(F₃/f₂ ·F) is a cubic modulo f₂. Wehave a rational map, : X ... Hdefined by (f₂,f₃) f₂ f₃. It fails to be regular along thelocus where f₂ and f₃ acquire a common linear component. Ourmain result gives an explicit resolution of the indeterminaciesof as well as of the singularities of H. 2000 Mathematical Subject Classification: 14C05, 14N05, 14N10,14N15.     

A stable manganese(V)-oxo corrolazine complex

The synthesis and characterization of an oxomanganese(V) corrolazine, (TBP)8(Cz)Mn(V)O (2), are reported. This remarkably stable high-valent complex is obtained from the stoichiometric reaction of (TBP)8(Cz)Mn(III) (1) with m-CPBA and is easily purified by standard chromatographic methods on silica gel at room temperature. Complex 2 exhibits a diamagnetic 1H NMR spectrum indicative of a low-spin d2 Mn(V)O species. LDI-TOFMS of 2 shows the predicted isotopic envelope at m/z 1426.8. This envelope shifts to higher mass as expected after the facile exchange of the terminal oxo group with H218O. The resonance Raman spectrum of 2 either in solution or in the solid state shows a strongly enhanced Raman band for the stretching mode of the Mn-oxo bond, which also shifts as expected upon 18O substitution: 2(16O), 979 cm-1; 2(18O), 938 cm-1 (in CH2Cl2). Initial reactivity studies show that 2 rapidly transfers the terminal oxo ligand to PPh3, resulting in the quantitative formation of OPPh3 and concomitant reduction of 2 back to 1. Complex 2 is the first example of an oxomanganese(V)-porphyrinoid complex that can be isolated at room temperature.     

Generalization of the determinants for trace-potent linear operators

SupposeA is a bounded linear operator on a separable Hilbert space withA ^m of trace class for some positive integerm. A generalized determinant for the operatorI–A is defined, its properties studied and this determinant is then used to exhibit an inversion formula forI–A.     

Layer-by-layer assembly of ordinary and composite coordination multilayers

Coordination self-assembly of bishydroxamate-based metal-organic multilayers on gold employing a layer-by-layer (LbL) approach was investigated. It is shown that the solution chemistry of the participating metal ion has a marked influence on the composition and properties of the multilayers. Use of Ce4+ and particularly zirconium(IV) acetylacetonate (Zr(acac)4) solutions in the ion-binding step of multilayer construction leads to multilayers with a near-stoichiometric metal ion-to-ligand ratio, suggesting a structure close to that predicted by a simple coordination self-assembly scheme. On the other hand use of a ZrCl4 solution as the source of metal ions in the multilayer construction leads to a multilayer with greater thickness and a large excess of Zr(IV), evenly distributed between the organic layers. In the latter case, a ratio of ca. 1:2 between the excess Zr and oxygen, as well as long-term Zr4+ binding experiments showing deposition of ZrO2, suggest the formation of a zirconia-type nanophase between the bishydroxamate organic repeat units during multilayer self-assembly. Hence, while the multilayer prepared using Zr(acac)4 solution appears to represent a "true" coordination-based structure, the one prepared using ZrCl4 is best described as a composite organic-ceramic multilayer. Composite multilayers prepared in this way display different properties from those of the stoichiometric ones, such as improved dielectric behavior and higher stiffness. Even greater mechanical stability is obtained with multilayers constructed using alternate binding of ZrCl4 and Ce4+. The concept of LbL formation of coordination-based composite organic-ceramic structures may be useful in obtaining nanometer-scale structures with tunable properties.     

Multienzyme system for dihydroxyacetone phosphate-dependent aldolase catalyzed C-C bond formation from dihydroxyacetone

A multienzyme system composed by recombinant dihydroxyacetone kinase from Citrobacter freundii, fuculose-1-phosphate aldolase and acetate kinase, allows a practical one-pot C-C bond formation catalysed by dihydroxyacetone phosphate-dependent aldolases from dihydroxyacetone and an aldehyde.     

Electrostatically arranged cytochrome c-fullerene photoelectrodes

We have developed a molecular-level switch-a C(60)/cytochrome c modified ITO electrode-that reversibly transmits and processes solar energy.