Clustering Structure Of Be Isotopes Studied With Deformed RMF+BCS Method

Relative mean-field (RMF) theory, as one of the very successful micro-models, was setup by unifying the merits of various successful classical models. RMF theory was introduced in detail first in this paper. Movement equation of nucleon is given with Euler-Lagrange equation and movement equation of mesons with Klein-Gordon equation beginning with Lagrangian density of nucleons and mesons, Electromagnetic field equation is given beginning with Lagrangian density of photon. And some equations used to describe other characters of nuclei have been deduced from above equations.Studying clustering structure for neutron rich nuclei in Be isotope with RMF model is our method. The calculations were based on harmonic oscillator basis of deformed axis. Thus we must use polar coordinate for simplifing the calculation. Because single particle's blocking effect in investigating even-even nuclei of Be isotope nuclei, the BCS theory was adopted to deal with pair correlation. Calculating with BCS theory for neutron-rich nuclei with less nucleon and more valence neutrons can decrease the excited energy. So results calculated with this method are in better agreement with property of clustering structure.The calculated nucleon density distributions and deformation parameters are analyzed to look for the clustering structure. The calculated density distribution suggests two a clusters in nucleus of Be isotope. Nucleons taken up ground state lie in (1P3/2,1P1/2)4,(1P3/2,1P1/2)4states. The clustering structure is well-established in both ground and excited state. Comparing the clustering structure in all nuclei of Be isotope, we found it changed regularly. The 2 a structure shows weakly in 10Be, while in other Be isotopes exists clearly. The valence neurons form as neutron skin and neutron halos. Moreover, we conclude that neutron skin and neutron halo plays a crucial role for the clustering structure.