Convergence in divergent series related to perturbation methods using continued exponential and Shanks’ transformations
摘要
Divergent solutions are ubiquitous with perturbation methods. We utilise continued functions, such as the continued exponential, to converge divergent series in perturbation approaches for energy eigenvalues of helium, the Stark effect and the Zeeman effect on hydrogen. We observe that convergence properties are obtained similar to those of the Padé approximation, which is extensively used in literature. Free parameters are not used, which influence the convergence, and only the first few terms in the perturbation series are implemented.