Photoluminescence of calcite crystals of different origins

We have studied the photoluminescence of calcite crystals. In the blue region of the photoluminescence spectrum of calcite crystals obtained from Siberia (Russia) and from Saaremaa Island (Estonia), three strongly overlapping luminescence bands due to intrinsic defects are observed. Luminescence due to impurities in the crystals are hardly detectable. The experimentally measured time dependence of the luminescence intensity for the indicated luminescence bands is compared with the dependences obtained as a result of a calculation based on a proposed model for the luminescence center. Better agreement between experiment and calculation is achieved if the model of the luminescence center includes a metastable level with electron ejection energy of 4 meV; the characteristic time for the radiative transition is 1.3 nsec. Studying the time dependence of the luminescence at different wavelengths within the indicated bands allows us to conclude that the photoluminescence (three bands) is due to one type of luminescence center. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 498–501, July–August, 2006.