Hydrodynamic model in isospin channels.
The Steinwedel-Jensen hydrodynamic model is generalized to study isovector collective modes excited in charge-exchange reactions. Results are given for the energy splittings between the different isospin components of the giant dipole and monopole resonances recently observed in (p,n) and (..pi../sup +- /,..pi../sup 0/) reactions. The quenching of the ..delta..T/sub z/ = +1 excitation strength in Nnot =Z nuclei with respect to the N = Z case is also discussed.