Electric Multipole Radiation in Direct Nuclear Reactions

The properties of excited 0 + states, including the electric quadrupole and monopole radiation strengths B(E2), E0, and the Rasmussen parameter X, in direct (t,p) nuclear reactions are investigated within the framework of a nucleon clustering model employing a combined Woods-Saxon and Coulomb potential.The influence of the Coulomb interaction on 0 + states is analyzed through its effect on nuclear density distributions and configuration mixing.Coulomb repulsion between protons enhances the difference between the charge radii of the ground and excited states, leading to an increase of the monopole E0 matrix element.The resulting spatial expansion of the wave functions also produces a slight enhancement of electric quadrupole E2 radiation probabilities.The inclusion of the Coulomb potential modifies the structure of the nuclear wave functions and leads to a redistribution of the (t,p) reaction strength among several 0 + states with large cross sections.The results are applied to the isotopes 152,154 Sm and 154,156 Gd.