Application of the multiphonon method to the study of the vibrational states with K=0 in heavy deformed nuclei.

Abstract

Listen

Translate article

The multiphonon method based on ${K}^{\ensuremath{\pi}}$${=0}^{\mathrm{\ensuremath{-}}}$ and ${K}^{\ensuremath{\pi}}$${=0}^{+}$ phonons is applied to heavy mass deformed even nuclei, such as Th, U, and Pu isotopes. Special emphasis is put on the location and properties of the ``two phonon'' states. Relative to an harmonic situation, the calculated energy spectra are systematically dilated. The octupole vibrations with ${K}^{\ensuremath{\pi}}$${=0}^{\mathrm{\ensuremath{-}}}$ present larger anharmonicities than the vibrations ${K}^{\ensuremath{\pi}}$${=0}^{+}$ which, in these nuclei, are found to be mainly of pairing nature. The two modes appear to be weakly coupled. The ``two phonon'' states are predicted to have an energy of about 1.7 to 2.0 MeV and keep some collective character through their electromagnetic transitions to the ``one phonon'' states. These conclusions are at variance with those of the quasiparticle phonon nuclear model of Soloviev et al.