Ni(CO)4 - A test of the Hartree-Fock approximation for transition-metal compounds

The geometry of Ni(CO)₄ has been optimized with basis sets of varying size, the larger ones being of near-Hartree-Fock quality. The best basis sets give a metal-ligand bond distance 0.097 A longer than experiment. Relativistic corrections have been obtained at the level of first-order pertubation theory, and yield a NiC bond contraction of 0.026 Å.     

A comparative study of the dissociation of protons into low-mass pπ+π− systems in coherent and incoherent proton-nucleus collisions at 18.6 GeV/c

A decay angular moments analysis has been performed on 8500 pπ⁺π^? events produced by the interaction of high-energy protons with nuclear targets. The analysis was carried out separately for the low-t, coherent events and high-t, incoherent events. The moments of the two samples show significant differences and possible reasons for such differences are discussed.     

Soft π−p and pp elastic scattering in the energy range 30 to 345 GeV

Differential cross sections for π^?p and pp elastic scattering have been measured at incident momenta ranging from 30 to 345 GeV and in the t range 0.002 (GeV/c)² ? |t| ? 0.04 (GeV/c)². From the analysis of the data, the ratio ? (t = 0) of the real to the imaginary parts of the forward scattering amplitude was determined together with the logarithmic slope b of the diffraction cone.The results on the real parts confirm the validity of the forward dispersion relations at high energies. Using the dispersion relations, it was shown that the experimental data on ?_{π?p(t = 0)} require a continuous rise of the total πp cross sections, at least up to the energy of 2000 GeV, thus revealing a close similarity in high-energy behaviour of πp and pp interactions.The results on the slope parameters from this experiment together with the analysis of the available world data demonstrate that the existing experimental data are consistent with the hypothesis of a universal shrinkage of the hadronic diffraction cone at high energies. The value of the asymptotic shrinkage parameter α_p^′ was found to be independent of the kind of the incident hadron and of the momentum transfer in the t range |t| ? 0.2 (GeV/c)² : 2α_{p^′ = ± 3 (GeV/c)^?2}.     

Negative Beantwortung einer Approximationsfrage

Ohne Zusammenfassung     

A Stereocontrolied Entry to Racemic Eremophilane and Valencane Sesquiterpenes via an Intramolecular Diels-Alder Reaction

A stereocontrolied route to racemic eremophilane and valencane sesquiterpenes is described via a common intermediate 15 , accessible from an intramolecular Diels-Alder reaction. ¹³ C - NMR .-shift assignments of the bicyclic intermediates and products are presented.     

Statistical inference of 2-type critical Galton–Watson processes with immigration

In this paper the asymptotic behavior of the conditional least squares estimators of the offspring mean matrix for a 2-type critical positively regular Galton–Watson branching process with immigration is described. We also study this question for a natural estimator of the spectral radius of the offspring mean matrix, which we call criticality parameter. We discuss the subcritical case as well.     

The use of the high pressure hydrothermal method for tailored synthesis of zeolites without structure directing agents. Instance: Synthesis of natural zeolites with 5-1 building units

Abstract

The synthetic counterparts of natural alumosilicate zeolites containing 5-1 structural building units have been synthesized by simulating the natural hydrothermal formation conditions. Synthetic glasses of the respective zeolite composition were used as starting materials, while distilled water under hydrothermal conditions was used as pressure and reaction medium. No structure directing agents, additional solutions or sol-gel material has been employed.

The experience of former investigations on the tailored synthesis of alumosilicate zeolites showed, that 220°C is the expected temperature of maximum gain. Synthesis time was always 60 d. Synthesis pressure for mazzite (MAZ), mordenite (MOR), fer-rierite (FER), epistilbite (EPI) and dachiardite PAC) was 1 kbar while bikitaite (BIK) could only be synthesized at 2 kbar pressure.

The results of the investigations on hand show, that this process can be applied for the tailored synthesis of zeolites with completely new properties (e.g., semiconducting frameworks).     

Phthalocyanine-aniline dyad constructed with click electrochemistry: a novel hybrid electrochromic material

Journal of Solid State Electrochemistry - A novel hybrid electrochromic material, dyad of poly 4-azidoaniline (PANI-N3) and manganese phthalocyanine bearing terminal alkynyl moieties (TA-MnPc), was...