Theory of spin-peierls transitions in chains of exchange clusters

A theoretical approach to the analysis of magnetostructural phase transitions of chain polymeric heterospin complexes is suggested. The approach is based on a model of the spin-Peierls transition in chains of exchange clusters. The chain elasticity parameter is found to be a main factor determining the order of phase transition.     

An X-ray photoelectron study of the electronic structure of Cu(II) complexes with dia- and paramagnetic derivatives of 2-imidazoline

The electronic structure of free radicals and Cu(II) complexes with the nitronyl nitroxide radical and aminonitrone is studied by X-ray photoelectron spectroscopy (XPS). N1s XPS spectra of nitrogen atoms of Cu(II) complexes with aminonitrones confirm the diamagnetic nature of the ligands. The binding energies of the main peak and the intense satellite structure in the Cu2p _3/2,1/2 spectra of the complexes under study correspond to the Cu(II) state. The structure of the satellite in the Cu2p _3/2,1/2 spectrum depends on the environment of the metal ion.     

Scintillation Characteristics of Lithium Fluoride Crystals Doped with Tungsten Oxide

Russian Physics Journal - Results of investigation of the spectral-kinetic parameters of a new LiF–WO3 luminophore in broad time interval 10–108 ns after the termination of the exciting...     

Tests of the CBM Rich readout and Daq prototype

The CBM RICH detector is an integral component of the future CBM experiment at FAIR, providing efficient electron identification and pion suppression necessary for the measurement of rare dileptonic probes in heavy ion collisions. An overview of the CBM RICH readout and DAQ system prototype is given, consisting of the PADIWA preamplifier-discriminator board, the TDC-HUB board TRBv3, and DAQ and analysis code in the CbmRoot framework. The laboratory setup built for studying the timing characteristics of the readout chain and the analysis results obtained using the laboratory measurements are presented. The fine time calibration and inter-channel delay correction techniques and their implementation and effect are discussed.     

Influence of phase interface properties on mechanical characteristics of metal ceramic composites

The paper reports on theoretical study to elucidate the influence of geometric (width) and mechanical characteristics of phase interfaces on strength, ultimate strain, and fracture energy of metal ceramic composites. The study was performed by computer simulation with the movable cellular automaton method and a well-developed mesoscale structural composite model that takes explicit account of wide transition zones between reinforcing inclusions and the matrix. It is shown that the formation of relatively wide “ceramic inclusions-binder” interfaces with gradual variation in mechanical properties allows a considerable increase in the mechanical properties of the composite. Of great significance is not only the interface width but also the gradient of mechanical properties in the transition zone. The presence of defects and inclusions of nano- and atomic scales in interface regions can increase internal stresses in these regions, induce a steep gradient of mechanical properties in them, and hence decrease strain characteristics and fracture energy of the composite.     

Crystal structure of mixed-ligand complexes of the Ni(II) heterospin bischelate withiso-butyl alcohol and 1,4-Butanediol

The crystal structures of the mixed-ligand complexes of the heterospin bischelate bis [2,2,5,5-tetramethyl-l-oxyl-3-imidazoline-4-(3’,3’,3’-trifluoro-1’-propenyl-2’-oxiato)nickel(II) (NiL₂) with iso-butanol and 1,4-butanediol NiL₂(i-C₄H₉OH)₂ and NiL₂[HO(CH₂)₄OH], respectively, are determined. The crystal structure of the NiL₂ complex with the normal butyl alcohol NiL₂(n-C₄H₉OH)₂ and the structure of CoL₂[HO(CH₂)₄OH] are refined. Translated fromZhurnal Strukturnoi Khimii, Vol. 38, No. 5, pp. 930–945, September-October, 1997.     

Problem of a wide variety of products in the Cu(hfac)2-nitroxide system

The stereochemically flexible Cu(hfac)(2) metal-ligand system when combined with polyfunctional nitroxides leads to a variety of solids with varying structure and composition. While investigating the products of Cu(hfac)(2) interaction with spin-labeled pyrazole 4,4,5,5-tetramethyl-2-(1-methyl-1H-pyrazol-4-yl)-imidazoline-3-oxide-1-oxyl, we have isolated a family of (12) heterospin compounds differing in structure and composition in the solid state. In synthetic systems, these compounds often cocrystallize and must be separated mechanically. It is also shown that minor variation of the structure of the solid heterospin complex can substantially change the magnetic properties of compounds.