Bulg. J. Phys. vol.27 no.1 (2000), pp. 071-077
Properties of the Low-Lying Excited States in Medium and Heavy Even-Even Nuclei Around Closed Shells
Ch. Stoyanov 1, N. Lo Iudice 2, N. Tsoneva 1, M. Grinberg1
1Institute for Nudear Research and Nuclear Energy, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
2Dipartimento di Scienze Fisiche, Universitá di Napoli Federico II and Istituto Nazionale di Fisica Nucleare, sezione di Napoli Complesso Monte S. Angelo, via Cintia, I-80126, Napoli, Italia
go back1Institute for Nudear Research and Nuclear Energy, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
2Dipartimento di Scienze Fisiche, Universitá di Napoli Federico II and Istituto Nazionale di Fisica Nucleare, sezione di Napoli Complesso Monte S. Angelo, via Cintia, I-80126, Napoli, Italia
Abstract. The properties of low-lying states in 136Ba, 144Nd and 94Mo are investigated within the quasiparticle phonon model. It is shown that the strong quadrupole interaction in the particle-particle channel leads to the appearance of low-lying isovector excitations. Two branches, an isoscalar and an isovector ones, are thus observed in the low-energy sector of the spectrum. Both branches show peculiar regularities in the E2 and Ml transitions.