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Conference Papers Year : 2022

A case study in the photoionization of atomic anions

Abstract

Good models require accurate data and it is often believed that variational principles such as the Hylleraas-Undheim-MacDonald theorem provide a foolproof method for obtaining accurate energy levels. This however does not apply to energy differences nor to wave functions and hence to quantities relevant to astrophysics such as oscillator strengths and cross sections.Negative ions, in particular those of carbon and oxygen, are of fundamental interest for the understanding of electron correlation and play an important role in astrophysics and atmospheric physics. Until recently, there was only one experimental absolute cross section available for the photodetachement of C−, which was also used to calibrate many data for other systems such as oxygen, despite the fact that no calculations could reproduce it.Using modern technologies based on lasers, animated crossed beams and velocity map imaging, it is now possible to measure absolute cross sections and angular distributions with fewer assumptions on experimental parameters such as beam profiles, opening the possibility of performing a thorough study of experimental uncertainties.Advances in computing power and development of more rigorous numerical methods allows ab initio calculations to be performed in an extensive and systematic way, with the possibility of establishing error bars on the theoretical results.These advances have allowed the long-standing discrepancy between theory and experiment for the photodetachment of C− to be resolved.
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Dates and versions

hal-04194277 , version 1 (02-09-2023)

Identifiers

  • HAL Id : hal-04194277 , version 1

Cite

Mariko Dunseath-Terao. A case study in the photoionization of atomic anions. Taming the Uncertainty Monster: Lessons from Astrochemistry (TUMLA), Université de Rennes, Jul 2022, Rennes, France. ⟨hal-04194277⟩
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