  The recently improved information on the stellar (n,gamma) cross sections of
neutron-magic nuclei at N = 82, and in particular of 142Nd, turned out to
represent a sensitive test for models of s-process nucleosynthesis. While these
data were found to be incompatible with the classical approach based on an
exponential distribution of neutron exposures, they provide significantly
better agreement between the solar abundance distribution of s nuclei and the
predictions of models for low mass AGB stars. Particular attention is paid to a
consistent description of s-process branchings in the region of the rare earth
elements. It is shown that - in certain cases - the nuclear data are
sufficiently accurate that the resulting abundance uncertainties can be
completely attributed to stellar modelling. Thus, the s process becomes
important for testing the role of different stellar masses and metallicities as
well as for constraining the assumptions for describing the low neutron density
provided by the 13C source.
