On the Convergence Issue for Multi-Poles Conversion from Reich-Moore Formalism

Abstract

Multi-poles representation of resonance parameters is one of the most prospecting methods which can be applied in On-The-Fly Doppler broadening cross sections in resolved resonance range with high performance. However, there is numerical instability issue occurring in converting the non s-wave poles for higher angular momentum states from Reich-Moore resonance formula. This paper presents some preliminary solutions including implementation of simultaneous root finding method, restart capability, shift factor approximation cancelation along with arbitrary precision, to achieve the convergence of more poles for the higher orbital angular momentum.