Three-body calculations of elastic Deuteron-helium-4-scattering with faddeev equations

The Faddeev equations are applied to the Deuteron-⁴He system. For the interactions between the particles squarewell potentials are used. In order to solve the Faddeev equations, thet-matrix is approximated by one separable term. The phaseshifts of the elastic Deuteron-⁴He scattering are calculated. It is shown, that the separable approximation by only one term is insufficient for such calculations.     

Elastic neutron transfer in the scattering of Si isotopes

Angular distributions of the elastic scattering of ²⁸Si on ²⁹Si and ³⁰Si have been measured for incident beam energies at E = 65 and 70 MeV with a time-of-flight spectrometer for heavy ions. At 70 MeV the neutron transfer ³⁰Si(²⁸Si, ²⁹Si)²⁹Si was observed in addition to the elastic channel. The pronounced oscillations in the elastic scattering distributions are interpreted as being due to an elastic transfer of neutrons between the colliding nuclei during the scattering process. This assumption is in accordance with some general features of the data and allows for the extraction of spectroscopic factors of the transferred neutrons.     

Phänomenologische Behandlung der elastischen Streuung von Spin-1-Teilchen an Spin-0-Teilchen

The elastic scattering of spin 1 particles by spin 0 particles is treated in terms of the WolfensteinM-matrix. The purpose of these calculations is to find a method which allows to measure vector and tensor polarization of a spin 1 particle beam scattered by a spin 0 target and to find out experiments which determine all parameters of theM-matrix. The scattering cross section for double and triple scattering has been calculated. The discussion shows, that the use of a polarized ion source is much more favorable than the conventional double and triple scattering technique.     

Nuclear level mixing (NLM) experiments on polarized Na atoms chemisorbed on a W(110) surface

Nuclear level mixing (NLM) experiments were performed on polarized Na atoms chemisorbed on a clean and oxygen covered W(110) surface. Components of the electric field gradient tensor generated by the electronic environment of the nucleus were determined. Advantages and disadvantages of this method if compared to NMR measurements are listed briefly. The results are discussed in the framework of simple models.     

Computing reaction paths of a bifurcation reaction: an action wave-front-based perspective

Application of Hamilton–Jacobi (HJ) equation to reaction systems which involve energy barrier(s) leading to the product is relatively new. Such problems are described by a new class of HJ equation, called the generalised HJ equation. This new HJ equation renders an anisotropic propagation for the wave front. In this paper, we describe the adaptation of the fast marching method (FMM) and the generalised HJ equation to understand a new class of reaction process where the energy barrier does not lead to the product; instead, a new class of states are detected along the reaction path of such reactions. These states are valley-ridge inflection point, branching point and potential energy ridge. Such reactions are characterised as bifurcation reactions. We have identified a new classical wave front, called the reaction action front (RAF) which distinctly separates the reaction system into a reactant zone and a product zone connected by a third zone, called ‘neck’. The RAF is an important tool to understand the bifurcation reaction and the associated reaction paths. We have also introduced a convenient way to compute the reaction path force (RPF) using the FMM. The RPF for a bifurcation reaction significantly differs from the reactions with energy barrier, and so, the RPF provides vital information about the occurrence of branching of a path. The method has been tested for the isomerisation reaction of methoxy radical (H₃C) to hydroxymethylene radical (H₂?OH).     

Reorganisation of electronic shells after stripping

Depolarization (i.e. dealignment) after stripping of a fast nuclear spin polarized sodium ion beam and its dependence on the charge state is investigated experimentally. A model of the population mechanism of the He-like fraction is discussed. The importance ofK-vacancies and autoionizing three electron systems is stressed.     

Chemisorption of Li and Na on iridium surfaces: An investigation with nuclear spin polarized atoms

The chemisorption of Li and Na on clean and oxygen covered polycrystalline iridium was investigated using nuclear spin polarized alkali atoms. During adsorption on the surface the moments of the nuclei act as microscopic probes. The nuclear quadrupole moments of the alkali atoms are interacting with the electric field gradient. The interaction reflects the charge distribution around the nucleus. The nuclear magnetic moments are interacting with magnetic fields generated by the magnetic moments of electrons.