Low temperature scattering with the R-matrix method: the Morse potential

TL;DR

This paper introduces a new R-matrix computational approach for analyzing ultra-low temperature atom-atom collisions modeled by the Morse potential, validated against analytic solutions and showing excellent agreement.

Contribution

The paper develops and tests a novel R-matrix method for low-temperature collision studies, providing a validated framework for future reactive and non-reactive collision analysis.

Findings

Excellent agreement between R-matrix results and analytic solutions

Validated the method for eigenphases and scattering lengths

Progress towards a general approach for ultra-low energy collisions

Abstract

Experiments are starting to probe collisions and chemical reactions between atoms and molecules at ultra-low temperatures. We have developed a new theoretical procedure for studying these collisions using the R-matrix method. Here this method is tested for the atom -- atom collisions described by a Morse potential. Analytic solutions for continuum states of the Morse potential are derived and compared with numerical results computed using an R-matrix method where the inner region wavefunctions are obtained using a standard nuclear motion algorithm. Results are given for eigenphases and scattering lengths. Excellent agreement is obtained in all cases. Progress in developing a general procedure for treating ultra-low energy reactive and non-reactive collisions is discussed.