Effect of interaction in a particle-particle channel on properties of high-excited states

The effect is studied of interactions in a particle-particle channel on the properties of high-lying excited states of even-even spherical nuclei. Manifestation of interactions in a particle-particle channel is studied for the excitation energies up to 30 MeV. In a random phase approximation an excitation energy equation is obtained for the case when the hamiltonian in a particle-hole channel includes isovector and isoscalar multipole forces, whereas in a particle-particle channel the constants of multipole forces, ksup(nn), ksup(pp), ksup(np), are not equal to one another. In numerical solutions performed for the Sm isotopes an assumption is used that ksup(nn)=ksup(pp)=ksup(np)=ksub(lambda). The interaction in a particle-particle channel weakly (though notably) affects the distributions of B(E2) values of collective particle-hole states of 144Sm. This effect is still more evident for sup(146-150)Sm. Consideration of interactions in a particle-particle channel leads to qualitative change in the distribution of a contribution from two-quasi-particle component for the normalization of a one-phonon state (psub(jsub(1)jsub(2))sup(lambdai))sup(2) for some two-quasi-particle states of semimagic nuclei. The interaction in a particle-particle channel may heavily manifest itself in the (pt) reaction cross section, in which reaction the finite nucleus is semimagic