Effects of single-particle potentials on the level density parameter

The new definition of the energy dependence for the level density parameter including collective effects depends strongly on the semi-classical approach. For this method, defining an accurate single-particle potential is of great importance. The effect of the single-particle potential terms, which are central, spin-orbit, harmonic oscillator, Woods-Saxon and Coulomb potential, both for spherical and deformed cases, on the level density parameter was investigated by examining the local success of the global parameterizations of eight different combinations of these terms. Among these combinations, the sum of the central, spin-orbit, harmonic oscillator and Coulomb potentials, gives the most accurate predictions compared with experimental data. The local selections of the global parameterizations show that the single-particle models, which are based on the Woods-Saxon potential as the main term, are more suitable candidates than the models based on harmonic oscillator potential to extrapolate away far from stability. Also it can be concluded that the contribution of the Coulomb interaction, both around the closed and open shells is not neglectable.