Absorptions- und Fluoreszenzspektren des Systems KCl:Sm²⁺ bei tiefen Temperaturen

Abstract

Sharp emission line spectra of Sm²⁺ in KCl single crystals are observed up to 40 °K. From these it is possible to verify the idea of a substitution of a regular cation by an impurity ion and of a simultaneous association of a cation vacancy in the nearest neighbourhood [1/2 (110)]. This means that the crystal field at the place of the bivalent Samarium has the site symmetryC _2v . A cubic symmetry does not explain the spectra. It is possible to identify the line groups with the transitions, which are permitted by reason of the selection rules, and to set up the energy level diagram of the Sm²⁺ ion in KCl.

The separation of the single impurity-vacancy complexes was reached by quenching the crystals from 650 °C to room temperature.

The assumption of excitation exchange between neighbouring Samarium ions explains the spectra of the non-quenched crystals. The number of emission lines is determined for two different orientations of two dipole complexes towards one another. An interpretation of the absorption spectra of Sm²⁺ in KCl is proposed.