Hyperfine structure-sensitive chromatography

Mustapha Laatiaoui (Johannes-Gutenberg-Universität and Helmolttz Institut, Mainz, Germany)

Atomic spectra, consisting of discrete lines of different color, have long been observed for most chemical elements, in the laboratory and even from stars, and are key ingredients in understanding the cosmic origin of matter. Their precise spectroscopy provides insights not only into relativistic- and QED effects and how they influence the electronic structure of an atom, but also into single-particle nuclear effects via the spin and magnetic moment, and collective nuclear properties of shape and size via the quadrupole moment and mean-square charge radius [1]. In the region of the heaviest elements, it constitutes a valuable contribution to nuclear structure studies of deformed atomic nuclei near the predicted island of stability of superheavy elements. 

Currently however, optical spectroscopy stops at nobelium [2] (Z = 102). In order to push the spectroscopy frontier to the next heavier element, lawrencium (Z= 103), a new concept of Laser Resonance Chromatography (LRC) has been proposed [3], developed [4], and meanwhile commissioned. It exploits electronically state-resolved chromatography to measure the change in the ground state population by laser resonance excitation of sample ions to their higher excited levels, so that neither fluorescence detection nor resonance ionization is required for spectroscopy.

In my talk, I will first introduce important aspects of optical spectroscopy, its observables, and its uniqueness in studying fundamental properties of atomic nuclei in different regions of the Segré chart. I will then focus on recent advances in the spectroscopy of heavy nuclei and their relevance to the search for the island of stability, before introducing the LRC concept. Finally, I will discuss the potential implications of this work on lawrencium spectroscopy and beyond. 

References

[1] P. Campbell, et al.,PPNP 86(2016) 127.
[2] M. Laatiaoui et al., Nature 538 (2016) 495. 
[3] M. Laatiaoui et al., PRL 125, 023002 (2020). 
[4] E. Romero-Romero et al., Atoms 10(3), 87 (2022).