Resolution and interpretation of the luminescent spectra of some solids at low temperatures

Abstract

Luminescent inorganic solids may be divided into a number of classes. Some, like the uranyl salts and rare earth salts, show luminescence in the pure state, and some, like the Lenard and Klatt sulphides, seem to require a Small trace of impurity. The alkali halides, which may be rendered luminescent by prolonged heating in the vapour of the alkali metal, by electrolysis, or by exposure to short waves, may possibly be regarded as belonging to the second class, since it its generally recognized that the luminescence is connected with the presence of neutral atoms which must be considered as impurities in the ionic lattice. The chromium-activated substances studied so extensively by Deutschbein (1932) appear to belong to a third class. The intimate relations which have been found between the line-like emission and absorption spectra of the first class suggests that their luminescence may be quite simply explained as a kind of resonance phenomenon. Indeed, in the case of the rare earths the spectra appear to have been satisfactorily interpreted in terms of electronic transitions of the metallic ion. But, in spite of the very large amount of work on the second class of luminescent substances, a satisfactory explanation of their luminescence is still lacking. This is chiefly due to the fact that their spectra generally consist of broad and featureless bands. Various workers have claimed to have resolved these very broad bands into a number of partial bands, and Schmidt (1932) and Schellenberg (1932) have attempted to establish general series relationships among the partial band maxima. The resolution, however, has been obtained partly by visual observations and partly by reconstruction of the broad bands from a number of assumed partial bands. Howes (1928) obtained by visual spectrophotometry distinct structure in the bands of some of the alkali earth sulphides. His results will be referred to later in this paper. Tanaka (1921) carried out an extensive series of observations on the cathodo-luminescence of a large number of substances activated by various impurities and deduced the existence of a frequency interval characteristic of the activator. But as many of his numbers are the result or rearranging the slight fluctuations which appear on the visually observed spectrophotometric curves, the validity of his deductions is very doubtful.

Fundamental Coordination Chemistry, Environmental Chemistry, and Biochemistry of Lead(II)

“…There have been no detailed theoretical studies of lead-thiolate CT bands, and very little work in general has been reported on the absorption spectroscopy of Pb(II) coordination complexes. Although the absorption spectra have been reported for solid-state Pb(II) alkaline earth sulfides (69)(70)(71), these data have not been analyzed extensively. In addition, much of the data that have been reported (69)(70)(71) are ambiguous due to insufficient information on sample preparation and composition (95).…”

“…As early as 1952, Klotz et al (50) reported absorption spectra attributed to lead [Pb(II)] binding to proteins (37,(51)(52)(53). Even earlier, the absorption spectra of both aqueous (54)(55)(56)(57)(58)(59)(60) and solid-state (61-68) lead-doped alkali halides had been reported, as well as the absorption spectra of some Pb(II) doped alkaline earth compounds (69)(70)(71)(72)(73).…”

Photoluminescence, photoelectric emission and enhanced thermionic emission from strontium oxide

“…The observation of a blue-green or blue-white photoluminescence in sprayed strontium oxide coatings was reported briefly by Mee (1963). Cathodoluminescence has been investigated by Ewles (1938), Noga and Nakamura (1954) and Gandy (1958). Ewles found a weak luminescence consisting of four resolvable emission lines centred at about 3.2 ev; later work by Ewles and Curry (1950) suggested that this luminescence might be due to activation by a lead impurity.…”