Fluorescence and Relaxation Dynamics of Cesium in Argon Matrices: Multiple Trapping Sites and Host-Guest Interactions

TL;DR

This study explores the fluorescence and relaxation behaviors of cesium atoms in cryogenic argon matrices, revealing complex spectra, host-guest interactions, and multiple trapping sites through spectroscopy and simulations.

Contribution

It provides new insights into the trapping environments and spectral characteristics of cesium in argon matrices, supported by combined experimental and computational analysis.

Findings

Identification of two dominant trapping sites with distinct spectral features

Observation of large Stokes shifts and slow relaxation effects

Spectroscopic evidence of host-guest interactions and lattice reorganization

Abstract

We investigate the fluorescence and relaxation dynamics of Cs atoms embedded in a cryogenic argon matrix using spectroscopy measurements combined with diatomic-in-molecule (DIM) simulations. The data reveal complex emission spectra, large Stokes shifts, and slow relaxation effects, indicating strong host-guest interactions and substantial lattice reorganization. Although the spectra are superimposed on a broad background, possibly due to low-symmetry, defect-related, or grain-boundary trapping sites, the main spectral structure is consistent with two dominant trapping environments that give rise to two triplet absorption features with distinct fluorescence behavior of the doublet and singlet components. Polarization measurements further suggest that these sites may differ in symmetry, although a unique structural assignment remains difficult