Investigation Of The Isovector Giant Dipole Resonance In Hot Nuclear Matter

The series of volumes, Contemporary Concepts in Physics, is addressed to the professional physicist and to the serious graduate student of physics. The subject of many-body systems constitutes a central chapter in the study of quantum mechanics, with applications ranging from elementary particle and condensed matter physics to the behaviour of compact stellar objects. Quantal size effects is one of the most fascinating facets of many-body physics; this is testified to by the developments taking place in the study of metallic clusters, fullerenes, nanophase materials, and atomic nuclei. This book is divided into two main parts: the study of giant resonances based on the atomic nucleus ground state (zero temperature), and the study of the y-decay of giant resonances from compound (finite temperature) nuclei.

The goal of this dissertation in to provide a systematic study of the nuclear excitation of the giant dipole resonance (GDR) using medium-energy light ions and lower-energy heavy ions, where the Coulomb excitation of the resonances is small. Also, the Coulomb excitation of multiphonon giant resonances by intermediate-energy heavy ions will be examined.

A review of some recent developments in the field of giant multipole resonances is presented. Particular emphasis is placed on directions that the authors feel will be followed in this field during the next several years. In particular, the use of high-energy heavy ions to excite the giant resonances is shown to provide exciting new capabilities for giant resonance studies. Among subjects covered are: Coulomb excitation of giant resonances, photon decay of giant resonances, the recent controversy over the identity of the giant monopole resonance, the most recent value for incompressibility of nuclear matter from analysis of giant monopole data, the isospin character of the 63 A/sup /minus/1/3/ GQR, agreement between (e, e/prime/) and (hadron, hadron/prime/) excitation of the giant quadrupole resonance, prospects for multiphonon giant resonance observation, and isolation of the isovector giant quadrupole resonance. 55 refs., 23 figs., 4 tabs.

An investigation of photoabsorption experiments in the spherical nucleus (141)pr, the quasispherical dynamically deformed (197)Au, and the statically deformed (165)Ho showed that the best function for the energy dependence of the reduced transition probability is given by the Breit-Wigner form rather than the Lorentz form of a resonance function. However, the form of the resulting measured cross section is of the Lorentz type. The dependence of the giant resonance width Gamma on the excitation energy was also investigated. The variation was found to be less than 1% per MeV if one considered the known isovector E2 resonances above the giant dipole resonance. Best fit values of the reduced transition probabilities for the three nuclei are given and compared to (e, e') results.

Nuclear incompressibility Knm is an important parameter in the nuclear matter equation of state (EOS). The locations of the isocalar giant monopole resonance (ISGMR) and giant dipole resonance (ISGDR) of nuclei are directly related to Knm and thus can give the most effective constraint on the value of the Knm. In order to determine Knm accurately, a systematic study of the ISGMR and ISGDR over a wide range of nuclei is necessary. Alpha inelastic scattering at small angles has been successfully used to study the ISGMR of heavy and medium nuclei where the monopole resonance is concentrated in a broad peak. For light nuclei (A

Giant resonances are collective excitations of the atomic nucleus, a typical quantum many-body system. The study of these fundamental modes has in many respects contributed to our understanding of the bulk behavior of the nucleus and of the dynamics of non-equilibrium excitations. Although the phenomenon of giant resonances has been known for more than 50 years, a large amount of information has been obtained in the last 10 years. This book gives an up-to-date, comprehensive account of our present knowledge of giant resonances. It presents the experimental facts and the techniques used to obtain that information, describes how these facts fit into theoretical concepts and how this allows to determine various nuclear properties which are otherwise difficult to obtain. Included as an introduction is an overview of the main facts, a short history of how the field has developed in the course of time, and a discussion of future perspectives.

This book presents recent results on experimental and theoretical studies of the interaction of heavy ions with nuclei at low and intermediate energies: the dynamics of fusion and decay of complex nuclear systems, the synthesis of superheavy elements, the synthesis and properties of exotic nuclei close to the proton and neutron driplines, nuclear fission, nuclear structure, and reactions with stable and radioactive ion beams. It also covers some aspects of applied physics research: track membranes and their applications, the use of polymers in medicine and electronics, production and application of radioisotopes for medical purposes, and environmental protection.