Study of the negative parity band in ¹¹⁶Sn

The negative parity states in ¹¹⁶Sn have been described as being caused by two- neutron quasiparticle excitation. However, in recent years, octupole correlations have drawn considerable attention to the description of the lower lying states in nuclei which have permanent stable octupole deformation. This phenomenon occurs when nucleons near the Fermi surface occupies levels of opposite parity and having angular momentum differing by 3ħ. Though the existence of the enhanced electric dipole and octupole transition rates are the primary and direct proof for such correlations, the odd-even spin staggering (S(I)) gives another indication for the same. For octupole correlations, S(I) have minima at odd spins which mean a cluster of states 3^-, (4^-, 5^-), (6^-, 7^-) and so on. Also, the measurement of dipole and quadrupole moment differentiates between the octupole vibration and octupole correlation where lowering of the negative parity band results in the case of the latter