Speaker
Description
The Gogny-based QRPA approach developed in CEA, DAM, DIF [1] can be applied to spherical as well as to axially deformed nuclei, from light (i.e. oxygen) to superheavy elements [2]. For electric and magnetic dipole modes, intensive computational efforts have been made to produce a large-scale data set of gamma-ray strength functions with as little as possible phenomenological corrections. The resulting photon strength functions have been shown to reproduce the bulk of experimental data with a high level of accuracy [3]. The most recent calculations also include the transition probabilities for the decay of the QRPA excited states down towards the ground state, regardless of the electromagnetic multipolarity.
In this talk, I will also present some successes obtained by the QRPA approach in the reproduction of additional experimental data. More particularly, the method has been applied to the N=100 isotones in order to describe their 4- isomeric states. Since the calculated half-lives of pure K=4 states are too large by several orders of magnitude, the Coriolis coupling between QRPA states has been introduced to reproduce and interpret the variation of the lifetime along the N=100 isotonic chain [4]. Such a coupling requires the calculation of transition probabilities between QRPA excited states that can also be used to describe microscopically and consistently the low-energy de-excitation photon strength function, known as the upbend, observed in Oslo data and of particular relevance for reaction and astrophysical studies.
(1) S. Péru and H. Goutte, Phys.Rev. C 77, 044313 (2008)
(2) S. Péru et al, Phys.Rev. C 83, 014314 (2011)
(3) S. Goriely et al., European Physical Journal A 55, 172 (2019)
(4) L. Gaudefroy, S. Péru et al, Phys.Rev. C 97, 064317 (2018).