[en] Energy density formalism calculations in semi-infinite nuclear matter are performed. Analytical solution of the Euler equation is given. Geometrical properties of the density are studied. Surface and surface symmetry energies are calculated and simple compact formulae are given

[en] The validity of the density-matrix expansion (DME) is investigated using two different interactions: the Brink and Boecker B1 force and the Campi-Sprung G-0 force. Simple parametrizations of the hamiltonian density are discussed and the connection between the DME and Skyrme-like forces is examined

[en] We study the finite size effect on the momentum distribution of an ensemble of A non-interacting fermions enclosed in a box. Analytical expressions are obtained in two limiting cases. It allows us to analyze the convergence of the momentum disribution toward the standard step function in the infinite medium. Applying our results to the nuclear case, we compare the changes in momentum distribution generated by the finite size of actual nuclei to those due to short range correlations. Both effects are shown to be of same order of magnitude

[en] A new functional of the density and its derivative is proposed to the kinetic energy density and the corresponding Euler equations are solved. Comparisons with Hartree-Fock results show a close agreement, particularly, for the shape of the density at the surface, for heavy as well as for light nuclei. The dynamical properties of this functional are tested in the case of the giant monopole resonance and are satisfactory

[en] Inhomogeneity terms in the expansion of the kinetic energy density are included and the Euler-Lagrange equations solved. Shell effects may be incorporated in a simple way. The study of spherical shapes of large systems is given as an illustration of the method proposed

[en] In quantum mechanics it is not possible to define a probability for finding a particle at position r with momentum p. Nevertheless there is a function introduced by Wigner, which retains many significant features of the classical probability distribution. Using simple one dimensional models we try to understand the very involved structure of this function

[en] We prove that in the semi infinite nuclear system the droplet model formula relating the surface symmetry tension to the neutron skin is satisfied provided there exists an hamiltonian density involving only the densities and its derivatives. We make a fully self consistent calculation in a slab. We finally make some comments about the case of finite nuclei

[en] Energy Density Formalism calculations in semi-infinite nuclear matter are performed. Analytical solution of the Euler equation is given. Geometrical properties of the density are studied. Surface and surface symmetry energies are calculated and simple compact formulae are given. It is known that the surface symmetry energy epsilonsub(delta)sup(s) plays an important role in the determination of fissions barriers heights, dipole resonance strength and formation of the neutron skin. However experimental uncertainties do not allow even a rough estimate of this quantity. From experimental masses, one can only extract a correlation between volume and surface symmetry energies, so that the values of epsilonsub(delta)sup(s) found in the literature lie in the range (-20, -160). On the other hand the theoretical calculation of epsilonsub(delta)sup(s) is not accurate: with the same interaction, the results can vary by 50%. Besides the Droplet Model two methods have been exploited i) a fitting procedure on calculated masses using an Extended Thomas Fermi (E.T.F.) calculation, ii) a direct H.F. calculation in the semi-infinite nuclear matter (SINM). The method proposed here combines both advantages: it gives directly epsilon sub(delta)sup(s) through a self-consistent ETF calculation in SINM. In the first part we study the SINM (N=Z). Exact integration of the Euler equation allows a detailed investigation of the nuclear surface shape which is shown to be poorly represented by the usual Fermi shape. We mention some consequences of this departure in the analysis of actual nuclei. We then calculate the surface energy epsilonsub(s). Finally we generalize the method to the asymmetric case N not= Z. Analytical formulae are proposed for epsilon sub(s) and epsilon sub(delta)sup(s). (author)

[en] Various methods to characterize the fragment size distributions in nuclear multifragmentation are discussed. The goal is to find the best signals of a phase transition associated to multifragmentation. The concepts of scaling and critical exponents are reviewed and the possibility to determine them in finite nuclei is examined. The fluctuations of the fragment size distribution and a possible signal of intermittency are also discussed. (author). 29 refs., 4 figs., 1 tab

[en] This is a study of: the finite size effect on the momentum distribution n(/sup →/k) of an ensemble of A non-interacting fermions enclosed in a box. Analytical expressions are obtained in the two limiting cases the Fermi momentum. The result is to analyze the convergence of toward the standard step function in the infinite medium. Applying results to the nuclear case, changes are compared in n(/sup →/k) generated by the finite size of actual nuclei to those due to short range correlations. Both effects are shown to be of same order of magnitude. The next step is to take into account the short range correlations in finite systems