Tracing the parameter dependence of quantum resonances with numerical continuation

Abstract

In molecular reactions at the microscopic level the appearance of resonances has an important influence on the reactivity. To study when a bound state transitions into a resonance and how these transitions depend on various system parameters such as internuclear distances, one needs to look at the poles of the S-matrix. Using numerical continuation methods and bifurcation theory, we develop efficient and robust methods to trace the parameter dependence of the poles of the S-matrix. Using pseudo-arclength continuation, we can minimize the numerical complexity of our algorithm. As a proof-of-concept we have applied our methods on a number of model problems.