Expanding the limits of nuclear stability at finite temperature.

Properties of nuclei in hot stellar environments such as supernovae or neutron star mergers are largely unexplored. Since it is poorly understood how many protons and neutrons can be bound together in hot nuclei, we investigate the limits of nuclear existence (drip lines) at finite temperature. Here, we present mapping of nuclear drip lines at temperatures up to around 20 billion kelvins using the relativistic energy density functional theory (REDF), including treatment of thermal scattering of nucleons in the continuum.

Dynamical Synthesis of ^{4}He in the Scission Phase of Nuclear Fission.

In the exothermic process of fission decay, an atomic nucleus splits into two or more independent fragments. Several aspects of nuclear fission are not properly understood, in particular the formation of the neck between the nascent fragments, and the subsequent mechanism of scission into two or more independent fragments. Using an implementation of time-dependent density functional theory, based on a relativistic energy density functional and including pairing correlations, we analyze the final phase of the process of induced fission of ^{240}Pu, and show that the timescale of neck formation coincides with the assembly of two α-like clusters.

Microscopic Description of 2α Decay in ^{212}Po and ^{224}Ra Isotopes.

A microscopic calculation of half-lives for both the α and 2α decays of ^{212}Po and ^{224}Ra is performed, using a self-consistent framework based on energy density functionals. A relativistic density functional and a separable pairing interaction of finite range are used to compute axially symmetric deformation energy surfaces as functions of quadrupole, octupole, and hexadecapole collective coordinates. Dynamical least-action paths are determined, that trace the α and 2α emission from the equilibrium deformation to the point of scission.

Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the ^{78}Ni Region: A Hint from Lifetime Measurements.

Lifetime measurements of excited states of the light N=52 isotones ^{88}Kr, ^{86}Se, and ^{84}Ge have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2;2^{+}→0^{+}) and B(E2;4^{+}→2^{+}) were obtained for the first time for the hard-to-reach ^{84}Ge. While the B(E2;2^{+}→0^{+}) values of ^{88}Kr, ^{86}Se saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g_{7/2}, 1h_{11/2}) space of an inert ^{78}Ni core, the value obtained for ^{84}Ge largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N≲49, extend beyond N=50.

How atomic nuclei cluster.

Nucleonic matter displays a quantum-liquid structure, but in some cases finite nuclei behave like molecules composed of clusters of protons and neutrons. Clustering is a recurrent feature in light nuclei, from beryllium to nickel. Cluster structures are typically observed as excited states close to the corresponding decay threshold; the origin of this phenomenon lies in the effective nuclear interaction, but the detailed mechanism of clustering in nuclei has not yet been fully understood.