Fluororganische Synthesen IV, 1-Fluor-1-organyl-cyclopropane und andere Cyclopropan-Derivate durch Anlagerungsreaktion von «Nachfolge-Carbenen»

Fluoroorganic Syntheses IV: 1-Fluoro-1-organyl-cyclopropanes and other Cyclopropane Derivatives by Addition of ?Successor-Carbenes”? Treatment of chlorodifluormethane or dichlorodifluoromethane with methyllithium in the presence of an olefin affords 1-fluoro-1-methylcyclopropanes in fair yields. Depending on the particular reaction conditions, 1,1-difluorocyclopropanes, 1,1-dimethylcyclopropanes and 1-chloro-1-methylcyclopropanes may be obtained as well. Butyllithium and phenyllithium give rise to analogous products.     

Electron beam effects on oxygen exposed aluminum surfaces

The damaging effects of electron beams during the acquisition of electron spectra have long been an obstacle in surface analysis. In order to understand the physico-chemical processes which take place under electron irradiation in an AlO system, we have carried out an experiment in which artifices, such as heating, charging, and gas contamination, were absent. We have observed with Auger Electron Spectra increases of the oxidation extent and the oxygen concentration on an oxygen exposed (111) textured polycrystalline surface under electron irradiation (5 keV, 9 × 10^?5 A/cm²). These increases were not observed on a clean surface, and were very feeble on a (100) single crystal surface. The increase of oxygen concentration was independent of residual gas pressure (3 × 10^?9 to 6 × 10^?10 Torr) and its composition; and therefore cannot be explained by gas contamination during the experimental period (about 70 min). We attribute the increase of oxidation degree to the transition of chemisorbed oxygen atoms into oxide through direct momentum transfer from the incident electrons. We suggest that the increase of oxygen within the irradiated area is due to the surface diffusion of chemisorbed oxygen atoms from outside the irradiated area. These oxygen atoms are excited by the electrons scattered from the vacuum chamber walls and gain energy through Franck-Condon type mechanism. The absence of chemisorbed oxygen atoms on (100) surface explains the near absence of these increases on this surface.     

Line shape of the collision-induced scattering in CF4

Results on the spectral shape of the collision-induced scattering (CIS) of CF₄ gas are obtained for densities up to 270 amagats (296 K). For low frequencies they are compared with dipole-induced dipole theory; for high frequencies a short distance-induced binary collision model describes the observed spectral shape fairly well.     

Molecular structure of biphenyl in an argon matrix

The infrared spectrum of biphenyl was measured in an Ar matrix at 20 K. A comparison of the results with the spectra of this molecule in the solid liquid states shows that the structure of biphenyl in the matrix is similar to that in the liquid state, that is, the molecule is non-planar.     

Mechanism of a secondary reaction during the coulometric determination of uranium in a mixture with iron

Summary The mechanism of a photochemical secondary reaction which takes place between iron and uranium during the coulometric determination of uranium is explained. As a result of this interfering effect lower uranium values are found. The appropriate working conditions to obtain reliable uranium measurements are indicated.We wish to thank Mr. H. L. Eschbach and Mr. V. Verdingh for their helpful comments when drafting this paper.     

Low mass πN enhancement in inelastic αp interaction

Evidence for an enhancement in the isospin $\text{I =}\text{1}\text{2}\text{π}\text{N}$ system at M = 1130 MeV/c² (Γ = 80 MeV/c²) has been found in the reaction αp → αx at an incident α-momentum of 4.00 and 5.08 GeV/c. A strong t-dependence of the cross section and a mass-slope correlation are seen as the main features of the data.     

Über die π-Elektronenstruktur dertrans-1,2-Di-(pyridyl)-äthylene, 3. Mitt.: Die SCF−MO−CI-Untersuchung

Zusammenfassung Mit dem SCF–MO-Verfahren in der -Variationsmethode wurde die -Elektronenstruktur dertrans-1,2-Di-(pyridyl)äthylene untersucht. Die Spektren werden berechnet, wobei man Wechselwirkung dereinzeln angeregten Singulett-Konfigurationen berücksichtigt. Die berechneten Übergangsenergien sind in guter Übereinstimmung mit gemessenen Werten.

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-Electron structure of trans-1,2-Di-(pyridyl)-ethylenes, III.: Application of the SCF–MO–CI method

The -electron structure oftrans-1,2-Di-(pyridyl)-ethylenes was studied by the SCF–MO-method in the variable -approximation. The electronic spectra were calculated using the singly excited singlet configurations for the CI treatment. The calculated transition energies are in good agreement with the experimental data.

     

Differential and channel cross sections for the reactions KL0p → KS0p and KL0p → Λ0π+ in the c.m. energy range 1605 to 1910 MeV

The differential and channel cross sections have been measured for the reactions K_L⁰p → K_S⁰p and K_L⁰p → Λ⁰π⁺ in nine energy intervals in the c.m. range 1605 to 1910 MeV. The regeneration reaction is a combination of the KN amplitudes (with I = 0 and 1) and the $\text{K}\text{N}$ amplitude (I = 1) and is very sensitive to the various KN phase-shift solutions, some of which show an exotic I = 0, P₁ resonance. Our results have been expressed in terms of frequency distributions and cross sections, normalised by the Λ⁰π⁺ reaction. These results have been compared with the predictions of various partial-wave analyses. Qualitatively we can eliminate the P₁ non-resonant solution, though no solution correctly predicts our results.