Investigation Of The Cluster And The Nucleon Correlation In Light Nuclei Based On The Microscopic Nuclear Model

The investigation on nuclear microscopic structure is one of the most im-portant topics in nuclear physics.The understandings of nuclear structures and properties are getting more and more explicitly with the development of the ex-periments in nuclear field.Based on the available data,many nuclear models have been proposed to study the structure and the property in nuclei,in which nuclear shell model is one of the most widely accepted nuclear microscopic models.Be-sides,benefiting from many experimental results on nuclear cluster structure in recent years,the study on the nuclear cluster model becomes popular and many important results have been obtained.In the early studies of nuclear microscopic structure,people mainly focus on the studies of the average nucleon-nucleon interaction.However,with the deeper theoretical understanding on nuclear correlation,and many experimental Ineasurements about the nuclear cluster structure and the nuclear pairing effect,the studies of the extra correlation freedom are taking more and more atten-tion.The nuclear microscopic structure can be investigated by adding the extra nucleon-nucleon correlation into the existing model.It is beneficial for the precise description and discussion on nuclear structure.In this thesis,we firstly introduce the detailed expressions of nuclear wave function bases and the operators in the Hamiltonian of the system.Then,we give the analytical derivations of each Hamiltonian matrix element.Therefore,by con-structing the nuclear microscopic wave function,we can calculate various physical quantities including the binding energies of nuclei,and compare the calculated results with the experimental data.Depending on the different study objects,we mainly use two different ways to construct the corresponding wave functions and use different methods to calculate them respectively.One is Tohsaki-Horiuchi-Schuck-Ropke(THSR)wave function,where the variational Monte Carlo method is adopted.The other is Antisymmetrized Molecular Dynamic(AMD)method,which solves the corresponding wave functions and eigenvalues by diagonalizing the Hamiltonian matrix.Basing on the nuclear cluster model,we introduce the nucleon-cluster corre-lation in the THSR wave function of 9B nucleus and calculate its energy spectrum and density distribution.The results show that the nucleon-cluster correlation is very important in describing the properties of the 9B nucleus.Furthermore,we try to calculate the first 1/2+excited state of 9B,which has not been confirmed in experiment.Our result of the first 1/2+excited state of 9B provides theoretical reference for the further experimental confirmation on this state.We also investigate the nucleon-nucleon correlation in 10Be,10B and 10C nuclei,which is also called nucleon pairing effect.By analyzing the energies and the overlaps between wave function components,we find two different mechanisms to enhance the formation of deuteron-like pairs.These studies are very useful to further study the formation mechanism of nucleon pairs.We introduce a new formulation by including a new Gaussian weighted ba-sis of high momentum pairs in the high-momentum Antisymmetrized Molecular Dynamic(HMAMD)wave function,with which very rapid convergence is ob-tained in numerical calculation of 3H nucleus.It is interesting that the very high-momentum components in the new Gaussian HMAMD basis are found to be almost equivalent to the contact representation of the nucleon-nucleon pairs with very small nucleon-nucleon distance.The explicit formulation for the con-tact term significantly improves the numerical efficiency of the HMAMD method,and the corresponding contact correlation is very important for the formulation of light nuclei.According to the above studies on nucleon-nucleon correlation,we further improve the corresponding nuclear microscopic model and make more explicit understanding on the properties of nuclei.These works could be very useful for the future nuclear microscopic study.