[en] A critical survey is presented of several recent microscopic calculations of the optical-model potential for nucleons. Special emphasis is laid on those calculations which are sufficiently realistic to impose meaningful constraints on the parametric expressions used in the analysis of the experimental data

[en] The authors discuss the effect of the choice of Usub(p), an auxiliary single-particle potential energy, on the binding energy versus saturation density problem. (V.J.C.)

[en] The many-body theory and the low-density expansion developed by Brueckner, Bethe and others is combined to investigate several properties of the ground state and of single-particle excited states of symmetric nuclear matter. The following quantities are calculated from Reid's hard core nucleon-nucleon interaction: strength, energy-dependence, nonlocality and density-dependence of the real and of the imaginary parts of the optical-model potential, momentum distribution in the interacting ground state, dependence on density and momentum of the norm of a quasiparticle and of the effective mass, spectral function for particle states, saturation density and average binding energy per nucleon. No free parameter is adjusted in the calculation; good agreement is obtained with empirical values. It is shown that the effective mass has a narrow maximum at the Fermi surface; this is investigated in the framework of analytical models. (Auth.)

[en] The success of the shell-model and of the optical model implies the existence of quasi-stable single-particle states in atomic nuclei. We review the theoretical description of these quasi-particles. We describe an expansion for the calculation of their energy and life-time in nuclear matter. This approach is used to compute the optical-model potential, starting from Reid's hard core nucleon-nucleon interaction. Good agreement with empirical values is obtained. The optical-model potential in finite nuclei is calculated from a local density approximation. (author)

[en] We describe a calculation of the complex optical-model potential that is based on Brueckner's theory and on Reid's hard core interaction. We discuss successively nuclear matter and finite nuclei. The symmetry potential and the Coulomb correction due to the nonlocality are also computed and compared with empirical values. (orig.)

[en] We present a critical survey of recent theoretical calculations of the complex optical-model potential. We argue that calculations with the smallest number of parameters carry the most meaningful information, and we organize the discussion according to this criterion. (orig.)

[en] We investigate the origin of the density-dependence of the strength of an effective interaction previously derived from a Brueckner-Hartree-Fock calculation of the optical-model potential in nuclear matter. From the analysis of a model based on the Hartree-Fock approximation and on a Yukawa interaction with a Majorana exchange component, we study to what extent this dependence derives from the momentum dependence of the exchange contribution of the knock-on type. The model is also used to discuss zero-range pseudopotential methods for including this knock-on contribution. (orig.)

[en] The origin of differences found in recent microscopic calculations of the energy dependence of the effective mass in ₂₀₈Pb is investigated in the framework of various schematic models. These show the importance of shell effects and illustrate possible consequences of the use of a truncated configuration space in microscopic calculations. (orig.)

[en] We investigate the origin of the density-dependence of the strength of an effective interaction previously derived from a Brueckner-Hartree-Fock calculation of the optical-model potential in nuclear matter. From the analysis of a model based on the Hartree-Fock approximation and on a Yukawa interaction with a Majorana exchange component, we study to what extent this dependence derives from the momentum-dependence of the exchange contribution of the knock-on type. The model is also used to discuss zero-range pseudopotential methods for including this knock-on contribution. (orig.)

[en] The propagation of quantum mechanical wave packets in a mean field is discussed and illustrated in one-dimensional models. Nonlocal as well as energy-dependent mean fields are considered. The group velocity and the rate of natural spreading are compared with those which correspond to the propagation in free space. (orig.)