Speculations on the blue and red bands in the TL emission spectrum of albite and microcline

TL spectra of the feldspars albite (NaAlSi₃O₈) and microcline (KAlSi₃O₈) were recorded following X-irradiation at room temperature, and presented as isometric and contour plots. Bands at about 425 and 450 nm in both samples are ascribed to electron-hole recombinations in two types of hole centres. An intense band at the red can be attributed either to the excitation of Fe³⁺ ions by the blue emission, or to valence state conversion of the iron. The kinetic analysis of the glow curves enabled us to interpret the experimental results in terms of a discrete set of traps, and to suggest a model for some of the recombination centres. The analysis of the contour plots implies that at least part of red emission is independent of the blue band.