Pygmy dipole strength close to particle-separation energies - the case of the Mo isotopes
arXiv:nucl-ex/0512027 · doi:10.1140/epja/i2006-08-025-6
Abstract
The distribution of electromagnetic dipole strength in 92, 98, 100 Mo has been investigated by photon scattering using bremsstrahlung from the new ELBE facility. The experimental data for well separated nuclear resonances indicate a transition from a regular to a chaotic behaviour above 4 MeV of excitation energy. As the strength distributions follow a Porter-Thomas distribution much of the dipole strength is found in weak and in unresolved resonances appearing as fluctuating cross section. An analysis of this quasi-continuum - here applied to nuclear resonance fluorescence in a novel way - delivers dipole strength functions, which are combining smoothly to those obtained from (g,n)-data. Enhancements at 6.5 MeV and at ~9 MeV are linked to the pygmy dipole resonances postulated to occur in heavy nuclei.
6 pages, 5 figures, proceedings Nuclear Physics in Astrophysics II, May 16-20, Debrecen, Hungary. The original publication is available at www.eurphysj.org
References in corpus (5)
- Microscopic HFB+QRPA predictions of dipole strength for astrophysics applications
- Large-scale QRPA calculation of E1-strength and its impact on the neutron capture cross section
- Radiative strength functions in 93-98Mo
- Measurements of ultracold neutron lifetimes in solid deuterium
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- Connecting the Pygmy Dipole Resonance to the neutron skin
- Skyrme-Random-Phase-Approximation description of E1 strength in 92-100Mo
- An implementation of nuclear time-dependent density-functional theory and its application to the nuclear isovector electric dipole resonance