Rhodochrosite luminescence

Under powerful laser excitation with A = 532 nm manganese minerals, such as rhodonite and rhodochrosite, exhibit orange-red Ivuninescence even at room temperature. In rhodonite it is a band peaking at 620 nm with a halfwidth of 85-95 nm and a very long decay time of 5-6 ms (Fig. 4.67c,d). Such luminescence is typical for impurity Mn ". In rhodochrosite luminescence is more complicated. The luminescence band has a maximum near 640 nm and a half-width of 80 - 90 nm, which is typical for impurity Mn ", but a decay time of only 5-lOps is very short for such a center and indicates strong energy migration (Fig. 4.67a,b). 

It was established by steady-state luminescence spectroscopy that minerals of Mn, such as rhodonite, rhodochrosite, helvine, triplite, Mn-apatite, Mn-milarite and others, show dark red luminescence, mainly at 77 K, which is uncommon to impurity Mn ". The excitation center proved to be regular Mn ", while the emission center is Mn ", situated near some lattice defect (Gorobets et al. 1978 Gaft et al. 1981). 

Fig. 4.67. a-d Laser-induced time-resolved luminescence spectra of rhodonite and rhodochrosite demonstrating Mn " andNd centers... 

Fig. 5.48. Laser-induced luminescence of Mn bearing minerals (1-helvine 2-severgenite 3-Mn-mUarite 4-triplite 5-rodonite 6-rhodochrosite 7-Mn-calcite 8-Mn-curchatovite 9- Mn-tantalite 10-dgimboite 11-Mn-apatite) and its connection with crystallochemical structure a-rhodonite fo-rhodochrosite c-Mn-apatite d-carpholite (MnAl2(Si206)(0H)4 (Gaftetal. 1981)...

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