Single-particle resonant states with Green's function method

This study employs the relativistic mean field theory with the Green's function method to study the single-particle resonant states. In contrast to our previous work [Phys. Rev. C, 90: 054321 (2014)], the resonant states are identified by searching for the poles of Green's function or the extremes of the density of states. This new approach is highly effective for all kinds of resonant states, no matter whether they are broad or narrow. The dependence on the space size for the resonant energies, widths, and the density distributions in the coordinate space has been checked and was found to be very stable. Taking Sn-120 as an example, four new broad resonant states 2g(7/2), 2g(9/2), 2h(11/2), and 1j(13/2) were observed, and the accuracy for the width of the very narrow resonant state 1h(9/2) was highly improved to 1x10(-8) MeV. Further, our results are very close to those obtained using the complex momentum representation method and the complex scaling method.