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.