Dipole-strength distributions up to the particle-separation energies and photodissociation of Mo isotopes

Abstract

Dipole-strength distributions in the nuclides 92 Mo, 98 Mo and 100 Mo have been investigated in photon-scattering experiments with bremsstrahlung at the superconducting electron accelerator ELBE of the Forschungszentrum Rossendorf. A simulation of γ cascades was performed in order to estimate the distribution of inelastic transitions to low-lying states and thus to deduce the primary dipole-strength distribution up to the neutron-separation energies. The absorption cross sections obtained connect smoothly to ( γ , n ) cross sections and give novel information about the low-energy tail of the Giant Dipole Resonance below the neutron-separation energies. The experimental cross sections are compared with predictions of a Quasiparticle-Random-Phase Approximation (QRPA) in a deformed basis. Photoactivation experiments were performed at various electron energies to study the 92 Mo( γ , n ), 92 Mo( γ , p ), 92 Mo( γ , α ) and 100 Mo( γ , n ) reactions. The deduced activation yields are compared with theoretical predictions.