LUMINESCENCE AND MICROSTRUCTURE OF GA, IN AND TL CENTERS IN LABORATORY-DOPED NATURAL FELDSPARS

The doping of feldspars by Ga, In and Tl leads to the appearance of in tense specific emission bands. Their spectra and decay kinetics were m easured at 4-290 K in 2-8 eV spectral range. The lowest excited state of the impurity centre proves to be related to the excited P-3 State o f corresponding ns(2) ion. This is the reason for the long decay times (similar to 10(-3)-10(-4) s at 4 K), sharply depending on temperature . The higher excited states of the centres apparently are the activato r-oxygen hybrid states. Monovalent ns(2) ions possibly substitute Naor K+ ions in the K(Na)AlSi3O8 lattice. As follows from the lattice st ructure of alkali feldspars, they can have several different types of nearest neighbours.