(proton-neutron) continuum QRPA for neutron capture reaction on neutron rich nuclei toward the r-process application

斉藤 照之; 松尾 正之*

no journal, , 

The radiative neutron capture reactions in r-process evaluation are described mainly in terms of two mechanisms, the compound nuclear (CN) process and the direct capture (DC) process. Several studies suggest that the existence of resonances near the one neutron separation energy, such as the pygmy dipole resonance and the scissors mode, may influence r-process nucleosynthesis and its final abundance pattern. However, these discussions are based on the CN process. On the other hand, it is expected that the DC contributions may be dominanted in neutron-rich nuclei. Therefore we ask the question whether the resonances may also affect the r process not through the CN process. From this point of view, we have developed new neutron capture model based on Density Functional Theory and continuum QRPA. This model can take into account pair correlation, collectivity (e.g. surface vibrational modes) and resonances as intermediate states of (n,g) reactions. We will present our numerical calculations, Zn(n,g)Zn and Ge(n,g)Ge as examples, and discuss the effects of pair correlation, collectivity and resonances for the neutron capture reactions. In addition, we will show our recent attempts to apply to the case of (n,g) final states are odd-odd nuclei by using proton-neutron continuum QRPA.