Microscopic descriptions of nuclear electromagnetic transitions with the finite-amplitude method

Electromagnetic transitions of atomic nuclei, such as photoabsorption and gamma decay, play important roles in the understanding of reactions involved in nucleosynthesis and radiochemistry. The development of a reliable theoretical model for the descriptions of nuclear electromagnetic transitions is essential, since many nuclei involved in our applications are close to drip lines and have not been accessed by experiments. In this talk I will discuss our recent development of the finite-amplitude-method (FAM) code for the microscopic calculations of electromagnetic transitions within the framework of nuclear density functional theory. This method can be used to study the gamma decay of even-even, odd-A and odd-odd nuclei, as well as nuclear systems with a finite temperature. Our program is highly optimized and parallelized for large-scale calculations through the whole nuclear chart. We expect that our model will provide valuable nuclear-structure inputs for future reaction studies.