O efeito da temperatura em núcleos esféricos e deformados no formalismo de Dirac-Hartree Bogoliubov

• Autor(a) principal: Lisboa, Ronai Machado
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal Fluminense (RIUFF)
• Texto Completo: https://app.uff.br/riuff/handle/1/18697
• topic: Física Nuclear; Teoria de campo médio relativística; Equação de Dirac; Curva calórica; Núcleo finito com temperatura; Dirac-Hartree-Bogoliubov.; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA

Spherical and deformed nuclei are described in a nuclear mean-field relativistic theory in the Dirac-Hartree-Bogouliobov (DHB) approximation with temperature. We use a non-linear version of the Walecka Model (NL3) with a pairing interaction including temperature effects. The DHB approximation is an extension of the Hartree where short range correlations are considered, in particular those associated with nuclear pairing. We introduce a simplification, considering the nucleon wave functions in the Bardeen-cooper-schriffer (BCS) approximation ofr which the bi-components of the Dirac spinors are proportional. In this approximation the pairing correlations, the meson mean fields and the nucleos wave functions are calculated self-consistently. The main goal of this is to describe the ground state properties of hot nuclei, spherical and deformed, and to analyze how biding enegy, nucleon and charge radii, the nuclear spectra and the pairing gap energy vary with temperature. For the first time the temperature dependence of the pairing interaction is treated in a self-consistent way. Some thermodynamical properties such as the entropy and the excitation energy are obtained for serveral spherical and deformed nuclei as a function of the temperature. We present the caloric curve for some light and heavy nuclei and compare it to the nuclear fragmenttation exerimental data from heavy ion collisions, and discuss the nuclear liquid-gas phase transition. We also investigate the temperature effects and pairing correlations in the nuclear pseudospin symmetry.