SEMICLASSICAL APPROACH TO THE DESCRIPTION OF SEMIINFINITE NUCLEAR-MATTER IN RELATIVISTIC MEAN-FIELD THEORY

The surface and curvature energies as well as the surface thickness of semi-infinite nuclear matter are studied in the framework of the relativistic mean-field theory. The calculations are performed for linear and non-linear sigmaomega models, using a relativistic extended Thomas-Fermi method which includes gradient corrections to order h2BAR. The connections between the structure of the nuclear surface and the properties of uniform nuclear matter and the meson degrees of freedom are underlined. For reasonable saturation properties, it is shown that realistic values of the surface energy and the surface thickness can be simultaneously obtained in non-linear sigmaomega models. In this case the calculated curvature energy turns out to be considerably larger than the empirical estimates. We conclude that the relativistic effects in the mean-field approach cannot solve the so-called nuclear curvature energy puzzle. Comparisons with non-relativistic semiclassical calculations for Skyrme interactions are also made.