This study presents an in-depth experimental and theoretical analysis of the spectroscopy of cesium (Cs) atoms diluted in a solid argon (Ar) matrix at cryogenic temperatures, a system relevant to matrix isolation spectroscopy and crucial for the study of phenomena beyond the standard model of particle physics.
Our results [1] reveal a correlation between absorption spectra and temperature variations, and thanks to the analysis of Cs-Ar and Ar-Ar interactions, we propose new effective interaction potentials. The agreement between observed and simulated absorption line positions thus enriches our understanding of atomic interactions under these extreme conditions.

[1] T. Battard, S. Lahs, C. Crépin, and D. Comparat, Phys. Rev. A 108, 042820 – Published 26 October 2023

“Schematic diagram of the experiment”

“(a) Cesium absorption spectrum at different initial temperatures of the argon matrix; (b) Evolution of the spectrum as the matrix warms up after initial deposition at 8K. We can see that several spectral lines appear in addition to the atomic lines (red lines), generated by the different possible implantations of the cesium atoms (Image above).”