Thermodynamic Properties Of Hot-nuclei Formed In Intermediate Energy Heavy Ion Collisions And Finite-size Scaling Phenomenon Of Nuclear Liquid-gas Phase Transition Probes

The intermediate-energy heavy ion collisions,as the transition zone from low-energy heavy ion collisions to high-energy heavy ion collisions,have complicated reac-tion mechanism in which mean field and nucleon-nucleon collisions are interdependent and competing.It is of significance for us to understand the equation of state and liquid-gas phase transition of nuclear matter,which have been highlighted always,through investigating the thermodynamic or transport properties of nuclear matter formed in the heavy-ion collision process.According to these two points,this dissertation studies thermodynamic properties of hot nuclear matter formed during heavy ion collisions in the Fermi energy region as well as the size effect of liquid-gas phase transition probes in the nuclear de-excitation processIn the first work,we simulate 129Xe+119Sn central collision process in the Fermi energy region(15AMeV-100AMeV)and obtain nucleus phase space information in the framework of the isospin-dependent quantum molecular dynamics model.Applying these,thermodynamic quantities,such as temperature,mean density,chemical poten-tial,average momentum and transport quantities,such as viscosity coefficient,entropy density as well as their ratio,of nuclear matter formed in the central region([-3fm,3fm])amongst the heavy-ion collision process have been explored.Because the heavy ion collision is a dynamic process,we can approximately use the calculation formula of the mean free path according to statistical thermodynamics to calculate the mean free path of the nucleon under the maximum compressed state at different incident energies,and then calculate the in-medium nucleon-nucleon cross section.By comparing our results with the experimental results from Phys.Rev.C 90(2014)064602 explored by O.Lopez et al.,we found that the evolution of mean free path of nucleon and in-medium nucleon-nucleon cross section are in good agreement with the experimental results when the incident energy is greater than 40AMeV.In addition,the viscosity coefficient(?)and the ratio of the viscosity coefficient over the entropy density(?/s)of the hot nuclear matter in the central region under the maximum compressed state are derived It elucidated that ? and ?/s have a decreasing trend with incident energy.Moreover,as the incident energy is greater than 70AMeV,the ?/s approaches to a saturation value around 3/4?,which indicates that the hot nucleonic matter behave like perfect fluid as quark gluon plasma,even though here the particle is only hadronic level.In the second work,we apply the isospin-dependent quantum molecular dynamics model for the de-excitation of single nucleus.We simulate the de-excitation process of six different nuclei in different sizes(A=36,52,80,100,112,129 and Z=15,24,33,45,50,54,respectively),with the similar neutron-proton ratios(N/Z?1.3)and the same initial density(approximately equal to the saturation density ?0),within the temperature range of 0-20MeV.Using the phase space information of fragments at final state,the relationship between temperature and five different liquid-gas phase transition probes,such as the total particle multiplicity derivative(dMtot/dT),second momentum parameter(M2),multiplicity of intermediate mass fragments(IMF,NIMF),Fisher's power-law exponent(?)and Ma's Zipf's law exponent(?),are calculated so as to acquire the phase transition temperature(TA)and analyze their finite-size effects.Through the results,we found that the phase transition temperatures obtained from the IMF multiplicity,Fisher's power-law exponent and Ma's Zipf's law exponent have a strong correlation with the source size.This indicates that the finite size effect should be considered when probing the critical temperature(Tc)of infinite nuclear matter when using these three liquid-gas phase transition probes.Furthermore,by employing the finite-size scaling law,the critical temperature Tc and the critical exponent v are obtained for infinite nuclear matter with 1.3 neutron-proton ratio.It demonstrates that the critical temperature Tc=13.32±1.22MeV and critical exponent v=0.37±0.07,which is close to the value of 3D Ising or liquid-gas phase transition universal classes,for the infinite nuclear matter with N/Z?1.3.The above results have important reference value for the research on the properties of thermonuclear matter and liquid-gas phase transition.