Properties and dynamics of hot nuclei

Abstract

The finite temperature Hartree-Fock (FTHF) equations are developed to describe a thermally equilibrated nucleus. These are solved for the nuclei 4°Ca and 208Pb using a Skyrme interaction as the effective nucleon-nucleon interaction. Properties of these nuclei including excitation energy, entropy, and density are investigated as a function of the temperature of the nucleus. The linear response of a hot nucleus to a small amplitude time-dependent perturbation is derived, resulting in the finite temperature random phase approximation (FTRPA). These equations are solved consistent with the FTHF thermal ground state and Skyrme interaction. The properties of collective excitations of various multipolarity and the transition strength to excite them are investigated. The evolution of a hot and/or compressed nucleus is analyzed within the adiabatic approximation using a constrained FTHF method to describe the nucleus away from its equilibrium density. The development of a dynamical instability to long wavelength density fluctuations is described. The FTRPA equations are used to explore the onset of unstable multipole shape vibrations. Their role in the fragmentation of the nucleus is discussed.