Bound states of dipolar molecules studied with the Berggren expansion method

TL;DR

This paper introduces a novel application of the Berggren expansion method to study bound states of dipole-bound negative anions, demonstrating its effectiveness especially for weakly-bound states where traditional methods fail.

Contribution

The paper develops and benchmarks a non-adiabatic pseudopotential approach using the Berggren expansion to accurately analyze weakly-bound dipolar molecular states.

Findings

Good agreement with traditional methods for well-bound states

Berggren expansion effectively describes weakly-bound subthreshold states

Method outperforms direct integration for near-threshold energies

Abstract

Bound states of dipole-bound negative anions are studied by using a non-adiabatic pseudopotential method and the Berggren expansion involving bound states, decaying resonant states, and non-resonant scattering continuum. The method is benchmarked by using the traditional technique of direct integration of coupled channel equations. A good agreement between the two methods has been found for well-bound states. For weakly-bound subthreshold states with binding energies comparable with rotational energies of the anion, the direct integration approach breaks down and the Berggren expansion method becomes the tool of choice.