Spin-polarized LEED from low-index surfaces of platinum and gold

A relativistic theory of LEED has been applied, in the energy range from 0 to 200 eV, to (111) and (001) faces of Pt and Au. The calculated intensity versus energy profiles are in good agreement with experimental data, which, in particular, provides support for interpreting the observed surfaces as unreconstructed. As a consequence of strong spin-orbit coupling, large spin-polarization peaks are found, partly in conjunction with intensity maxima. As a rough guide to diffraction conditions, at which both polarization and intensity are sizeable, a simple kinematic model might be of some use.     

Effect of bulky ligands on one-dimensional platinum compounds

Summary Diaminedithiocyanatoplatinum(II) complexes react with iodine in ethanolic suspension to yield diamagnetic compounds of empirical formula Pt(diamine)(SCN)₂I, which exhibit properties characteristic of one-dimensional materials. Incorporation of bulky substituents in the diamine ligand does not prevent the extended z-axis interaction responsible for these properties, in contrast to the effect of large ligands upon cooperative phenomena in Magnus' Green Salt analogues.Reprintsof this article are not available.The phase cooperative phenomena refers to magnetic and electronic properties that arise form the interaction between neihbouring metal in the solid state.     

Algorithme matriciel et connexions d'ordre supérieur dans des fibrés non vectoriels

Résumé Le calcul des jets devenant rapidement presqu'inextricable, un calcul matriciel partiel est proposé qui pallie en partie à cet inconvénient et permet de mieux saisir la structure algebrique des jets holonomes (chap1). Cet algorithme est ensuite utilisé dans le calcul des jets et permet de définir des connexions d'ordre supériéur ainsi que les différentielles absolues correspondantes de manière très simple (chap2). Ceci généralise naturellement l'algorithme classique mis sous forme adéquate (voir introduction). Entrata in Redazione il 13 dicembre 1969.     

A Partioning Technique for Leontief Type Linear Programming Production Models

This paper studies the application of linear programming to the class of production planning problems which maximise profit subject to constraints on interacting production processes which can be represented by a static Leontief model. The method partitions the matrices involved in the solution process which enables the matrices involved in the computational process to become smaller at each iteration. Preliminary computational results show that the partitioning technique is quite efficient in solving such problems and should prove to be very effective on large-scale problems.     

Synthesen von Dibenzo[b,e][1,4]dioxin-2,3-chinonen,einschliesslich der Ecklonochinone A und B sowie der Isoecklonochinone A und B

Syntheses of Dibenzo[b,e][1,4]dioxin-2,3-quinones Including the Ecklonoquinones A and B and the Isoecklonoquinones A and B Oxidation of monomesyloxy-substituted pyrocatechols with MnO₂ in toluene using phase-transfer conditions leads in high yield to monomesyloxy-substituted dibenzo[b,e][1,4]dioxin-2,3-quinones with loss of one mesyloxy group. In this way, ecklonoquinone A ( 2 ), ecklonoquinone B ( 3 ), isoecklonoquinone A ( 43 ), and isoecklonoquinone B ( 44 ) were prepared. Their structures are based on X-ray analyses of ecklonoquinone-A leucoacetate ( 45 ) and the mesyloxy-substituted quinone 20 . The reddish-violet dibenzodioxin-diquinone 49 was prepared from an intermediate of the iso-series. The parent compound 1 has been synthesized in yields better than 50% from pyrocatechol and methyl 2,5-dioxo-2,5-dihydrobenzoate as oxidant and 2-methoxypyridin as catalyst. To rationalize the specific effect on the dimerisation step of the mesyloxy group, the intermediacy of 1,4-quinone monoacetals is proposed. This also applies to a proposed biogenetic scheme.