Poster Session

Poster Session I (4pm-6pm CDT)

4:00 pm – 6:00 pm, Tuesday June 4 // Session D00

Topics:

An implementation of a variational R-matrix method for the Dirac equation.

Poster 11

Presenter: Miguel Alarcon (Purdue University)

Author: Chris Greene (Purdue University)

This study introduces the adaptation of the eigenchannel R-matrix method to the Dirac equation. While implementations of the R-matrix method for the Dirac equation exist, none have utilized the eigenchannel framework, known for its high effectiveness and efficiency in the non-relativistic case. Our study aims to conduct a thorough theoretical analysis of the necessary modifications required to adapt the method to the relativistic equation. We also present a detailed analysis of Coulomb-specific generalized multichannel quantum defect theory parameters in the relativistic theory. This analysis allowed us to define a convenient basis of radial functions, enabling numerical analysis with a behavior similar to non-relativistic functions. We delve into the explicit form of these functions, a detail we found overlooked in the literature. Numerical explorations on the radium atom, treated as a two-electron problem using fitted potentials, were conducted. We studied photoionization cross sections and autoionization resonances, comparing them with non-relativistic effects. Additionally, we anticipate a comparison with novel measurements of the radium spectrum. Our ultimate goal is to utilize this method for future studies on the ionization of highly stripped ions.

Funding acknowledgement

We acknowledge support from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Award No. DE-SC0010545

POSTERS (157)