Fermi Energy Region Research Articles

Forward-angle yields of 2≤Z≤11 isotopes in the reaction of 18O(35A MeV) with 9Be

A systematic investigation of the forward-angle inclusive yields of 2≤Z≤11 isotopes produced in collisions of 18O projectile nuclei with a 9Be target in the Fermi energy region (35A MeV) is performed. The measurements were based on the use of the COMBAS double achromatic kinematical separator in the spectrometry mode at the Flerov Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research, FLNR (JINR, Dubna). The velocity, isotopic, and element distributions are presented. There is no unique mechanism that would explain the total set of results obtained in this experiment. A dominant role of low-energy reaction mechanisms is observed. The intensity of secondary beams of halolike nuclei 11Li, 12Be, and 14Be is determined.

Energy balance and the mechanism for very forward projectile fragments in the Fermi-energy region

Different schematic mechanisms are used to scale the observed energy change between forward and grazing angle fragments. A modification in the Goldhaber hypothesis is finally suggested to explain that the most probable velocity for forward fragments is very close to that of the beam.

Electronic structure and magnetism of Cr/Sn multilayer systems

The electronic structure and magnetism of Cr/Sn and Fe/Cr/Sn/Cr multilayer systems with monolayer Sn are studied by means of a first-principles method. The calculated hyperfine field at Sn site is significantly large (∼20 T) in Cr/Sn multilayers, while the value is remarkably diminished (∼4 T) in the case of Fe/Cr/Sn/Cr multilayers. This trend of the hyperfine field is consistent with recently reported experimental results. It is found that the hyperfine field at Sn site is determined by the spin magnetic moment at the interface Cr site. The most important feature in the electronic structure of the multilayer systems is the existence of an interface state at the Cr interface layer near the Fermi energy region.

Charge state of hydrogen in crystalline silicon.

An estimate is given for the relative stabilities of neutral and positive bond-center hydrogen interstitials and of negatively charged hydrogen at the antibonding site as a function of Fermi-level position. We predict the hydrogen-related donor level to be below the intrinsic Fermi level, and the existence of a Fermi-energy region around midgap where the neutral charge state is stable.