Un correlateur optique par filtrage chromatique fonctionnant en temps reel et en source etendue de lumiere blanche

Relief-type holograms were copied on PVC sheets from a master made on a photosensitive As-Se-Ge amorphous film. One hundred hologram copies could be printed successively without degradation of the reconstructed image quality. Typical diffraction efficiency of the copied hologram was about 2%.     

Recherches théoriques sur la structure électronique de molécules contenant des atomes hybridés en sp:

Résumé La méthode L. C. A. O. améliorée est utilisée pour étudier la structure électronique des molécules de vinylacétylène, de divinylacétylène et de butatriène, réduites à leur système . Les énergies des premières transitions N V sont en excellent accord avec l'expérience. Une relation entre l'indice de liaison mobile et la distance interatomique, pour des liaisons reliant des atomes hybridés l'un en sp et l'autre en sp ₂, est proposée.

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The improved LCAO theory is used to study the electronic structure of vinylacetylene, divinylacetylene and butatriene molecules, reduced at their system. The first N V transition energies are in excellent agreement with experiment. A relation between mobile bond order and bond distance, for bonds between sp and sp ₂ hybridized atoms, is proposed.

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Zusammenfassung Die elektronische Struktur der auf ihr -System reduzierten Moleküle Vinylacetylen, Divinylacetylen und Butatrien wird mit Hilfe der verbesserten LCAO-Methode untersucht. Die berechneten Energien der ersten N V-übergÄnge stimmen mit dem Experiment ausgezeichnet überein. Eine Beziehung zwischen Bindungsabstand und -Bindungsindex für Bindungen zwischen sp- und sp ₂-hybridisierten Atomen wird vorgeschlagen.

     

Evaluation of higher-order effective potentials with dimensional regularization

A new and simple method for evaluating high-order effective potentials is presented. It is based on the renormalization procedure of 't Hooft and Veltman used in conjunction with the scheme of dimensional regularization. Explicit calculations of the effective potential of a scalar field in two-loop approximation are carried out.     

Une méthode topologique pour L'etude de la propriété de ramsey

The paper is devoted to the study of some particular subclasses of the class of Ramsey sets, each one associated with an ultrafilter onΝ. By topological methods, we show that every such class contains the analytic sets. This generalizes the results of Silver and Mathias on this subject. Furthermore some applications to functional analysis are given, and a discussion of the additivity of these classes and of the Ramsey property of the ultrafilters is presented, under the hypothesis of Martin's Axiom.      

Synthese et etude par resonance magnetique nucleaire du carbone 13 et de l'etain 119 d'une serie de triorganostannyl-2 butanes

Optically active triorgano-2-stannylbutanes have been synthetized by different methods, one being the direct substitution of optically active s-butyl halides with triorganostannyl alkali metals. This route involves a complete or partial inversion of configuration at the chiral carbon atom. Carbon-13 and tin-119 NMR data are reported as support for the identification of eight triorgano-2-stannylbutanes. The special case of tetra(2-butyl)tin, with four identical chiral centres has been examined.     

Étude par rm13c d'alcaloïdes à squelette acridinone 9(10h) et pyrido(4,3b) carbazole(6h)

Both synthetic and natural acridinone and pyridocarbazole alkaloids have been studied by ¹³C NMR and simple model systems used for comparison.     

Properties of iodine complexes of monosubstituted polyacetylenes

Iodine complexes of six monosubstituted polyacetylenes with methyl, ethyl, propyl, pentyl, t-butyl, and phenyl substituents have been characterized by electronic spectroscopy. UV spectra allow the determination of the nature and the amount of active species, and photoelectronic spectra confirm the nature of these species. These measurements indicate the presence of iodine in the I and I₂ forms. The concentration of I is low (0.12–4.0 mol%), and it depends on the nature of the substitutent, but this amount does not decrease when the films are left under vacuum. On the other hand, the adsorption of ε high concentration of iodine is possible; this adsorption is governed by a diffusion mechanism and is reversible. Iodine doping leads to a cis-to-trans isomerization of the polymers, except for poly(3-3-dimethyl-1-butyne), which can be isomerized to the cis or to the trans form, depending on the solvent employed. Electrical properties of polymer I complexes are also reported. Conductivities of about 10^?4 Ω^?1 cm^?1 are obtained for all polymers in the presence of an excess of iodine.     

N.m.r. studies in the heterocyclic series: XVII—carbon-13 spectra of indazole derivatives

The ¹³C chemical shifts of 17 indazole derivatives are discussed as a function of substituent effects and the N-1—H or N-2—H structure of indazole. The presence in solution of the N-1—H tautomer is confirmed.     

Non-empirical pseudopotentials (PSIBMOL algorithm) for molecular calculations: The Rh2Cl2(CO)4 complex

The electronic structure of Rh₂Cl₂(CO)₄ in the ground state is computed using the recently proposed PSIBMOL (Pseudo-potentials + IBMOL/H) formalism. The drawing of the total and differential isoelectronic contour maps supports the idea that there does not exist any rhodium-rhodium bond in such a binuclear complex, the origins of the preferred bent conformation having to be found elsewhere.