Investigations of the Optical Spectroscopy of Atomic Sodium Isolated in Solid Argon and Krypton: Experiments and Simulations.

International audienceThe absorption spectra of thin film samples. formed by (lie codeposition of sodium vapor with the rare gases have long been known to consist of complex structures in the region of the atomic sodium "yellow-doublet" lines The photophysical characteristics of the associated luminescence (excitation/emission) spectra. indicate strong Interaction between the excited P state Na atom and the rare gases (Ar, Kr, and Xe) used as host solids. This system is, reinvestigated with new experimental spectroscopic results and molecular dynamics (MD) calculations The so-called "violet" site in Ar and Kr has been produced by laser excitation of thermally deposited samples The simulation of the "spray-on" deposition of thin Films enables identification of tetravacancy (tv) sites of isolation for ground-state atomic sodium in Ar while in Kr this site is found in addition to single vacancy (sv) occupancy various cubic symmetry sites were taken 11110 account to simulate absorption and emission spectra using acculate Interaction potentials For the Na center dot RG diatomics. The well-known 3-fold splitting in absorption. attributed to the Jahn-Teller effect, was very well reproduced but the simulated spectra for all the sites considered ire located in the low energy region of the experimental bands The evolution of the excited state Na atom is followed revealing the nature and symmetry of the Sites that. are transiently occupied. Consistent with the large Stokes shift observed experimentally, there is an extensive rearrangement. of the lattice In the excited state with respect to the ground state. Combining all the experimental and theoretical information, in assignment of experimental violet, blue, and led absorption features is established involving single vacancy, tetravacancy, and hexavacancy sites, respectively, in Ar and K