“Negative ions: Fragile Quantum Systems"

Negative ions, which are formed when an electron is attached to a neutral system, are unique quantum systems. The lack of a long-range Coulomb force causes the inter-electronic interaction to become relatively more important. As a consequence, the independent particle model, that adequately describes atomic structure under normal conditions, breaks down. Experimental studies of negative ions can therefore serve to probe electron correlation and hence be used to test theoretical models that go beyond the independent particle approximation [1]. In this talk, I will give an overview of experimental methods to study negative ions and present recent experimental highlights. This will include work using linear accelerators [2], storage rings[3] and the radioactive beam facility ISOLDE at CERN [4]. The common denominator is the photodetachment process, where one or more electrons are removed from a negative ion due to the absorption of a photon. The light sources used in the experiments are high resolution tunable nanosecond laser, high intensity femtosecond lasers, as well as synchrotron radiation. The experimental results will be compared with recent advanced many-body theoretical calculations. I will also present examples of applications of negative ions, which will include a discussion of their importance in astrophysic, heating of fusion plasmas, and in the field of accelerator mass spectrometry.

[1] D. J. Pegg, Structure and dynamics of negative ions, Reports on Progress in Physics 67, 857 2004.
[2] M. Eklund et al. Tomography of photoelectron distributions produced through strong-fieldphotodetachment of Ag-, PRA 102, 023114 (2020).
[3] Kristiansson et al. High-precision electron affinity of oxygen, Nature Communications 13, 5906 (2022)
[4] Leimbach et al.The electron affinity of astatine, Nature Communications, 11, 3824 (2020)

*) Within the framework of this project and the agreement between UNAM-UGOT, a coverage scholarship for a Master thesis project and two Ph. D. positions will be open for applications starting in September 2025.

Participante: Prof. Dag Hanstorp

Institución: University of Gothenburg, Sweden

Fecha y hora: Este evento terminó el Viernes, 14 de Febrero de 2025