Absorption spectra of lithium, sodium, and indium in solid xenon, krypton, and argon

Abstract

The absorption spectra of lithium, sodium, and indium in solid rare gases were obtained from samples formed and observed at 4.5ºK. A 1-meter concave grating spectrograph with photographic recording was used to obtain the spectra. Studies were made of lithium in xenon, krypton, and argon, and of sodium and indium in xenon. Rare gas to metal molar ratios of 250:1 to 1000:1 were used. Emphasis was placed on the study of the resonance transitions of the trapped atoms, 0 2 2 corresponding to transitions at 6708 angstroms for lithium, at 5890 angstroms and 5896 angstroms for sodium, and at 4102 angstroms for indium in the gas phase. In all cases a multiplet structure, whose center of gravity was shifted to higher energies with respect to the gas phase atomic transition, was observed. The multiplet structure is explained by assuming that one component is due to well isolated metal atoms and that the other components are due to metal-metal atom interactions between atoms trapped at nonnearest-neighbor substitutional sites in the host lattice. The energies of the interacting metal atoms are calculated from diatomic potential curves. The shifts with respect to the gas phase of the components due to well isolated atoms in xenon, krypton, and argon are calculated by using a Lennard-Jones (6-12) potential for the interaction between the trapped metal atoms and the rare gas atoms.