Zusammenfassung
The low-lying dipole strength of the open-shell nucleus Mo-94 was
studied via the nuclear resonance fluorescence technique up to 8.7 MeV
excitation energy at the bremsstrahlung facility at the Superconducting
Darmstadt Electron Linear Accelerator (S-DALINAC), and with Compton
backscattered photons at the High Intensity. gamma-ray Source (HI gamma
S) facility. In total, 83 excited states were identified. Exploiting
polarized quasi-monoenergetic photons at HI gamma S, parity quantum
numbers were assigned to 41 states excited by dipole transitions. The
electric dipole-strength distribution was determined up to 8.7 MeV and
compared to microscopic calculations within the quasiparticle phonon
model. Calculations and experimental data are in good agreement for the
fragmentation, as well as for the integrated strength. The average decay
pattern of the excited states was investigated exploiting the HI gamma S
measurements at five energy settings. Mean branching ratios to the
ground state and first excited 2(1)(+) state were extracted from the
measurements with quasi-monoenergetic photons and compared to.
gamma-cascade simulations within the statistical model. The
experimentally deduced mean branching ratios exhibit a resonance-like
maximum at 6.4 MeV which cannot be reproduced within the statistical
model. This indicates a nonstatistical structure in the energy range
between 5.5 and 7.5 MeV.
Nutzer