The rotational band on the 9− isomer in180Ta

The new radon isotope¹⁹⁷Rn was produced in the reaction¹⁶⁹Tm(³⁵Cl, 7n)¹⁹⁷Rn using bombarding energies from 5.6 to 6.1 MeV/nucleon. Fusion products were separated in-flight from the primary beam using a gas-filled recoil separator. The alpha particle energy and half-life of¹⁹⁷Rn were measured to be (7260±7) keV and (65 _?14 ⁺²⁵ ) ms, respectively. Another new alpha line was assigned to an isomeric state in¹⁹⁷Rn for which an alpha particle energy of (7356±7) keV and a half-life of (19 _?4 ⁺⁸ ) ms were obtained.     

K-theory of braided tensor ring categories with higher commutativity

We show that theK-theory of a Waldhausen categoryC with anA-ring structure is anA ring spectrum. If theA structure onC supports anE _n structure, so thatBC group completes to ann-fold loop space, thenK (C) is anE _n ring spectrum. In particular, theK-theory of the category of crossedG-sets,G a finite group, is anE ₂ ring spectrum.     

Mechanisms of antioxidant action: Chemical binding of a thiol antioxidant into polypropylene by means of uv irradiation

3,5-Di-t-butyl-4-hydroxybenzyl mercaptan (BHBM) became chemically combined to polypropylene to the extent of 68% of the antioxidant present when films containing BHBM were exposed to uv irradiation. In addition to the radical coupling reaction of the thiyl radical derived from BHBM with the polymer, a second technologically less useful process also occurs, leading to the formation of a derived stilbenequinone. The latter absorbs strongly both in the visible and in the near uv and consequently slows down the subsequent loss of the bound antioxidant from the polymer.     

Bond energies for molecules, clusters, and deposit systems

A new approach is suggested to the assignment of bond energies in molecules and clusters. It uses a shareholder principle for the redistribution of the shifts in atomic energies, which arise in a molecule, on the bonds. The scheme is directly suitable for semiempirical methods, where only one- and two-center terms occur. MSINDO calculations are performed to demonstrate the suitability of the approach for molecules and clusters. As an application the bonding in a deposit system is analyzed for the case of copper on magnesium oxide. It is found that copper atoms do not only bind to the preferred oxygen sites but also substantially to the magnesium sites. The copper-copper bonds are the strongest and will determine the structure of copper clusters on magnesium oxide surfaces.