{{High-spin states of Yb-156 have been studied via the Sm-144(O-16,4n)Yb-156 fusion-evaporation reaction at beam energy 102 MeV. The positive-parity yrast band and negative-parity cascade have been extended up to higher-spin states, respectively. The characteristics of the negative-parity sequence above the 25 state may related to the excitation from the nucleon in the Z = 64
The diffusion properties of fluorine ions in GaN are investigated by means of Time-of-Flight secondary ion mass spectroscopy. Instead of incorporating fluorine ions close to the sample surface by plasma, fluorine ion implantation with an energy of 180 keV is utilized to implant fluorine ions deep into the GaN bulk, preventing the surface effects from affecting the data analysis. It is found that the diffusion of fluorine-ions in GaN is a dynamic process, featuring a two-step process. A defect-assisted diffusion model is proposed to account for the experimental observations. Fluorine ions tend to occupy Ga vacancies induced by fluorine ion implantation and diffuse to vacancy rich regions. The fluorine ions become stable after continuous vacancy chains are significantly reduced or removed by thermal annealing. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim