On some problems in describing and employing radiative strength functions

• Published in: Physics of atomic nuclei Vol. 77; no. 10; pp. 1303 - 1312
• Main Authors: Kamerdzhiev, S. P., Avdeenkov, A. V., Achakovskiy, O. I.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.10.2014; Springer
• Subjects: Nuclear physics; Nuclei; Particle and Nuclear Physics; Physics; Physics and Astronomy; Giant Dipole Resonance; Strength Function; Fermi System; Atomic Nucleus; 68Ni Nucleus
• ISSN: 1063-7788; 1562-692X
• DOI: 10.1134/S1063778814090038

Problems that are associated with the description of radiative processes in low-energy physics for nuclear data and which can be solved within modern microscopic theory of the nucleus are discussed. This discussion concerns recent results in the theory of the pygmy dipole resonance and of the radiative strength function and the status of the Axel-Brink hypothesis. It is confirmed that coupling to phonon degrees of freedom must be taken into account in order to explain this resonance and the radiative strength function. By using the self-consistent generalized theory of finite Fermi systems, in which this coupling is taken into account, the pygmy dipole resonance is calculated for the 68 Ni and 116 Sn nuclei, and agreement with recent experimental data is obtained for the mean energy and for a 5% exhaustion of the sum rule for 68 Ni. For the example of the 68 Ni and 116 Sn nuclei, the E 1 radiative strength functions are calculated for the first time with allowance for coupling to phonons, and the microscopic cross sections for total E 1 photoabsorption that were obtained within the self-consistent generalized theory of finite Fermi systems are employed in these calculations.