Single particle spectrum of a nucleon in the harmonic oscillator mean field with spin-orbit coupling - a semiclassical view

We have presented the single particle spectrum for a particle in a mean field of isotropic harmonic oscillator with l.s coupling based on our semiclassical approach. It has been seen that this spectrum, without l.s coupling, exactly matches with the quantum mechanical one (without nuclear constraints). In this case, periodicity conditions give only pendulating orbits coinciding with l=0 axis, which fully support the observations reported by Bohr and Mottelson [28]. The orbits with l>0 are generated by reflecting the particle from the nuclear surface, instead of infinity, which is the usual nuclear constraint. The mean field strength is fixed by virial theorem. The resulting spectrum compares reasonably with the quantum spectrum for a particle enclosed in a perfectly reflecting walls. The variation of particle number with energy help us to identify the significant quantum numbers n and l in this semiclassical method. Finally, the l.s coupling splits each level and the splitting width of these level compares well with that of nuclear splitting. Thus the complete nuclear shell model (with magic numbers) is reproduced without any fitting parameter.