Decay properties of the 3^-₁ level in ⁹⁶Mo

The first excited 3−1 level of 96Mo was investigated in a high-statistics experiment using the 95Mo(n, γγ) cold neutron capture reaction. The measurements used the high cold neutron flux from the research reactor at Institut Laue-Langevin and employed the highly-efficient EXILL array to detect γ-ray coincidences. The recorded statistics allow identification of decay branches with only a small relative intensity including the 3−1 → 0+gs E3 decay. With the knowledge of the newly measured branching ratio and the known B(E3, 3−1 → 0+gs) transition probability, the lifetime of the 3−1 level was determined and, subsequently, the B(E1) strength of the other decay branches of the 3− 1 octupole phonon were calculated. The extracted electromagnetic decay strengths are compared to the systematics of the stable even-even molybdenum isotopes and values calculated in a Skyrme-force based quasiparticle random phase approximation and in a cluster approach. Additionally, the 3− 1 → 2 + iv decay branch to the low-lying 2+ iv quadrupole isovector level was observed.