On the possible application of LEED to the study of surface potential barriers

The structure of surface barrier resonances in LEED is shown to be strongly dependent upon the shape and position of the potential energy barrier at the crystal surface. This suggests that systematic high-resolution measurements of LEED intensities in the energy range of surface barrier resonances may be a useful tool for studies of surface barrier structure. Such measurements should be performed at several angles of incidence and at a variety of azimuths with primary beams of very low energy (<30 eV).Computations are presented for a model crystal surface of Cu(001) to illustrate these conclusions. The results are in agreement with McRae's model for the surface barrier resonance in LEED.     

Rotating nuclei in a semiclassical description

A recently proposed semiclassical method for extracting the smoothly varying part of the total energy of an independent particle system is applied to a rotating system. Expressions for the average density distribution, angular momentum, total energy and effective moment of inertia are given.     

Separation of histamine and its metabolites using glass capillary gas chromatography and a nitrogen detector

Complete separation of the TMS derivatives of histamine, 1-methyl histamine and 3-methyl histamine was achieved in two minutes in a 7 m × 0.25 mm column coated with SP 2250. Using NPD, histamine was detectable at levels as low as 20 pg. This offers a rapid, sensitive procedure with potential for clinical diagnosis and food analysis.     

The pion-nucleus many-body problem

Low energy pion-nucleus elastic scattering is discussed within the framework of many-body theory. In these considerations exchange of virtual ρ ad π mesons, as well as the π meson, are found to play an important role, producing effects like the Ericson-Ericson Lorentz-Lorenz effect. By inclusion of interactions in channels other than the pionic one, the pion-nucleus problem is brought into the context of other nuclear many-body problems, and various relations to the nucleon problem made use of .Some of the necessary parameters here are drawn from pionic atom work. With these and our deduced interactions the theoretically predicted cross-sections are found to be in good agreement with the experimental work.     

The direct reaction of the tBu-DAB ligand with SeCl4: a redox route to selenium-nitrogen heterocycles

The reaction of SeCl4 with the ubiquitous tert-butyl-substituted diazabutadiene ligand results in the isolation of a rare example of a 1,2,5-selenadiazolium cation, representing a novel route to Se-N ring formation; these heterocycles can be derivatised at selenium, which has led to the identification of a short Se...N secondary bonding interaction.