Fluorescence and relaxation dynamics of cesium in argon matrices: Multiple trapping sites and host-guest interactions
Phys. Rev. A 114, 032821 – Published 21 September, 2026
DOI: https://doi.org/10.1103/4f6z-cm2t
Abstract
We investigate the fluorescence and relaxation dynamics of Cs atoms embedded in a cryogenic argon matrix using absorption, fluorescence, and polarization spectroscopy, complemented by diatomic-in-molecule simulations. The data reveal complex emission spectra, large Stokes shifts, and slow light-induced evolution, indicating strong host-guest interactions and substantial lattice reorganization. The absorption spectrum contains two prominent tripletlike structures superimposed on a broad background that may arise from a distribution of low-symmetry, defect-related, or grain-boundary environments. Excitation-resolved fluorescence reveals related behavior within these two spectral groups, compatible with two dominant families of trapping environments, although contributions from additional sites and multiple relaxation pathways cannot be excluded. Polarization measurements indicate distinct relaxation behavior for one excitation band, but neither the experimental data nor the present calculations permit a unique structural assignment.
