NMR applications for a study of converted photochemical processes kinetics

The analytical expression describing dynamics of the nuclear magnetization with the use of double resonance nuclear magnetic resonance of a procedure of transfer of spin saturation under photo-induced chemical exchange is obtained. Three different experimental procedures for the definition of the effective rate constants and the quantum yield of responses are considered.     

Measure space automorphisms,the normalizers of their full groups,and approximate finiteness

We deal with the normalizer $\text{N}$[T] of the full group [T] of a nonsingular transformation T of a Lebesgue measure space in the group of all nonsingular transformations. We solve the conjugacy problem in $\text{N}$[T]/[T] for a measure preserving and ergodic T. Our results show that a locally finite extension of a solvable group is approximately finite.     

Experimental and numerical study of self-induced transparency in a neon absorber

Self-induced transparency on the neon transition 2s ₂(J=1)–2p ₄(J=2) is studied both experimentally by investigating the propagation of 3-nsec laser pulses at 1.15 µm in an absorber discharge and theoretically by a numerical integration of Bloch's equations and the wave equation.—The application of linearly and circularly polarized light corresponds to the interaction with a quasi-nondegenerate and degenerate transition, respectively. Pulse shapes, delays, and transmittancevs. input peak intensity are found in quantitative agreement with the calculated data. While with linear light polarization all SIT characteristics clearly appear, with circular polarization the pulse break-up and the oscillation of transmittance due to optical nutations are washed out.—The homogeneous linewidth derived from pulse delay data agrees with the value from conventional measurements. The results prove SIT useful as a quantitative spectroscopic method.Work supported by the Deutsche Forschungsgemeinschaft     

A new look at Bergström’s theorem on convergence in distribution for sums of dependent random variables

In his 1972Periodica Mathematica Hungarica paper, H. Bergström stated a theorem on convergence in distribution for triangular arrays of dependent random variables satisfying, a ?-mixing condition. A gap in his proof of this theorem is explained and a more general version is proved under weakened hypotheses. The method used consists of comparisons between the given array and associated arrays which are parameterized by a truncation variable. In addition to the main theorem, this method yields a proof of equality of limiting finite-dimensional distributions for processes generated by the given associated arrays as well as the result that if a limit distribution for the centered row sums does exist, it must be infinitely divisible. Several corollaries to the main theorem specialize this result for convergence to distributions within certain subclasses of the infinitely divisible laws.     

Anwendung derR-Wert-Methode auf isokonformere Cyclohexane: Kernsubstituierte [2.2]Metacyclophane

The applicability of theLambert-Buys-Criterion (R-Value-Method) is tested for the ten-membered ring of [2.2]metacyclophane. The torsional angles thus obtained from the vicinal proton spin coupling constants are in accordance with X-ray data and recent force field calculations. Consequently, further investigations could be performed regarding the changes of the basic geometry in substituted [2.2]metacyclophanes. Fourteen derivatives with different substituents and substitution patterns were studied and their conformational changes are discussed.

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Mit 7 Abbildungen

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VonH. Lehner auszugsweise vorgetragen am Organisch-Chemischen Institut der Reichsuniversität Gent, Belgien, am 27. Mai 1975.