Published 1984 | Version v1
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Study of various models of nuclear interaction potentials: nucleon-nucleus and nucleus-nucleus systems

Description

Several models, performed within a mean field theory, are developed for the calculation of nucleon-nucleus interaction potentials. The first part of the thesis deals with the nucleon-nucleus average interaction. It is mainly devoted to the calculation of dynamical corrections to the Hartree-Fock approximation. Two approaches are used: a microscopic model performed in the framework of the nuclear structure approach and a semi-phenomenological one, based on the application of the dispersion relations to the empirical imaginary potential. Both models take into account finite size effects like collectivity or threshold effects which are important at low energy. The Green's function properties are used for both models. The second part of this work is devoted to the interaction potential between two heavy ions. This calculation, which is performed in the framework of the sudden approximation, uses the energy density formalism (Thomas-Fermi approximation). It has been extended to finite temperature. At T=0 the experimental fusion barriers of heavy systems are reproduced within 4%. Their temperature dependence is studied. The proximity scaling is checked and a universal function is obtained at T=0 and at finite temperature. It is found that the proximity theorem is well satisfied on the average. The dispersion around the mean behaviour increases with increasing temperature. At last, P+A* and α+A* interaction potentials are calculated within a double folding model using a schematic effective interaction

Availability note (English)

MF available from INIS under the Report Number.

Abstract (French)

Plusieurs modeles de calcul de potentiels d'interaction nucleon-noyau et noyau-noyau sont developpes. Tous sont bases sur la notion de champ moyen. Deux parties peuvent etre distinguees. La premiere traite du potentiel moyen nucleon-noyau. Elle est essentiellement consacree au calcul des termes correctifs d'origine dynamique au potentiel Hartree-Fock, par ailleurs bien connu. Deux modeles sont developpes: un modele microscopique ayant pour cadre l'approche de structure nucleaire et un modele semi-phenomenologique base sur l'application des relations de dispersion au potentiel imaginaire empirique. Tous deux permettent de tenir compte des effets de taille finie des noyaux (collectivite, effets de seuil) qui sont importants a basse energie. Leur construction formelle est basee sur l'utilisation des proprietes des fonctions de Green. La deuxieme partie de ce travail traite du potentiel d'interaction entre deux ions lourds. Ce calcul, effectue dans le cadre de l'approximation soudaine utilise le formalisme de la densite d'energie (approximation de Thomas-Fermi). Il peut donc etre etendu a temperature finie. A temperature nulle, les barrieres de fusion experimentales des systemes de noyaux lourds sont reproduites a mieux que 4%. L'evolution de ces barrieres en fonction de la temperature est etudiee. Une loi d'echelle de proximite peut etre degagee. Cette propriete, bien verifiee a temperature nulle est encore satisfaite a temperature finie. La dispersion augmente cependant avec la temperature. Des potentiels d'interaction p+A* et α+A* sont d'autre part calcules dans le cadre d'un modele de convolution utilisant une interaction effective schematique. La loi d'echelle de proximite est encore satisfaite

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Additional details

Additional titles

Original title (French)
Etude de differents modeles de potentiels d'interaction nucleaire: systemes nucleon-noyau et noyau-noyau

Publishing Information

Imprint Pagination
348 p.
Report number
IPNO-TH--83-27