Researchers Maen Salman and Jean-Philippe Karr, affiliated with the University of Bordeaux in France, have recently published a study that delves into the precise calculation of the photodetachment energy of negative hydrogen ions (H⁻). Their work, appearing in the journal Physical Review Letters, offers a significant advancement in the understanding of this fundamental atomic process.
Photodetachment refers to the process where an electron is stripped away from a negative ion due to the absorption of a photon. In the case of negative hydrogen ions, this process is of particular interest due to their role in various plasma environments, including those found in certain types of fusion reactors. The researchers employed an exact three-body approach to calculate the nonrelativistic bound-state energy of the hydrogen anion, supplemented by corrections for relativistic effects, quantum electrodynamics, finite nuclear size, and hyperfine interactions.
The study reports a highly precise photodetachment energy value of 6083.06447 cm⁻¹ for the detachment to the hydrogen ground-state hyperfine level (F=0). This value is 220 times more precise than the best experimental determination to date, which was reported by Lykke et al. The researchers also extended their calculations to negative deuterium and tritium ions, yielding values of 6086.70676 cm⁻¹ for ²H⁻ (F=1/2) and 6087.87924 cm⁻¹ for ³H⁻ (F=0).
The practical applications of this research for the energy sector are primarily related to fusion energy. Negative hydrogen ions are crucial in the process of neutral beam injection, a technique used to heat plasma in fusion reactors. A precise understanding of the photodetachment energy can help optimize these processes, potentially improving the efficiency and performance of fusion reactors. Additionally, the study’s findings could contribute to the field of antihydrogen physics, where controlled photodetachment of H⁻ offers a path to producing ultracold antihydrogen for precision experiments.
This article is based on research available at arXiv.