Nuclear structure studies close toN = Z = 50.

The level structures in ^98,99Rh, and ⁹⁹Pd nuclei have been investigated through in beam γ-ray spectroscopic techniques following the ⁷⁵As(²⁸Si, xpyn) fusion-evaporation reaction at E_lab =120 MeV. These investigations were carried out using Indian-National-Gamma-Array (INGA) consisting of Compton-suppressed clover detectors at the Inter-University Accelerator Centre, New Delhi. The level structures observed in ⁹⁹Pd, and ^98,99Rh have been established up to ~11 MeV, 10 MeV and 16 MeV excitation energy and spin ~ 23ħ,23ħ, and 28ħ respectively. In the doubly-odd ⁹⁸Rh nucleus, new bandstructures and isomeric states have been identified at lower spins and new states below the previously identified 2⁺ ground state (T_1/2 = 8.5 m) are identified. In the present work ⁹⁹Rh structure have been observed similar to ¹⁰¹Rh which is based on p^1/2 and g^9/2 orbitals. Various positive and negative parity states in these nuclei are observed to be energetically more favored with respect to the neighboring ones, and are likely to be the maximally aligned states obtained by angular momentum coupling of the valence particles (holes). The level structures observed in Pd have been interpreted in the framework of a microscopic theorybased on the deformed Hartree-Fock (HF) and angular momentum projection techniques. Bandstructures at low excitation energy are based on the low-Ω vg_7/2 and vd_5/2 orbitals, have been observed in ⁹⁹Pd. Band structure at higher spins are reproduced with the v(g_7/2)² ⊗ v(g_7/2)^-1 ⊗ v(h_11/2)² ⊗ n(g_9/2)⁶ configurations. Observation of new E1 transitions linking the opposite parity vh_11/2 and vd_5/2 bands provide fingerprints of possible octupole correlations in ⁹⁹Pd. The extracted values of the B(E1)/B(E2) ratios for the lower levels in the vh_11/2 band are ~ 10^-7 [fm]^-2. [ABSTRACT FROM AUTHOR]