Reabsorption Lines of Oxygen and Water

Color centers in topaz can be produced by irradiation with fast neutrons and gamma-rays (Platonov et al. 1989). It was found that luminescence bands are connected with such color centers, which may be detected by steady state and time-resolved spectroscopy (Marques et al. 2000). The detected luminescence bands have been connected with both impurities and structural changes. 

Simulated interstellar matter, such as forsterite, enstatite and magnesite, has been irradiated by gamma-rays and fast neutrons and their induced spectra have been investigated. For the forsterite and magnesite after irradiation the spectra exhibit rather intensive peaks at approximately 650 and 660 nm, respectively. Besides that, forsterite demonstrates several narrow lines the strongest one at 610 nm (Koike et al. 2002). 

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Reabsorption Lines of Oxygen and Water 5.13.1 Apatite Luminescence Spectroscopy... 

Fig. 4.6. Reabsorption lines of molecular oxygen and water in laser-induced time-resolved luminescence spectra of sedimentary apatite (francolite)...

P site, Mn in Ca(l), Ca(ll) sites and adsorption on carlxMiate-fluor-apatite surface reabsorption lines of molecular oxygen and water have been found and ascribed (Gaft et al. 1996 Gaft et al. 1997a, b, c) (Figs. 4.2, 4.3, 4.4, 4.5, 4.6 and 4.7). 

Gaft M, Reisfeld R, Panczer G, Oiampagnon B (1997c) Reabsorption lines of molecular oxygen and water in natural apatite. Opt Mater 8(1-2) 143-149 Gaft M, Reisfeld R, Panczer G et al (1998) Laser-induced time-resolved luminescence of minerals. Spectrochim Acta A 54 2163-2175... 

Such unusual phenomena as reabsorption lines of molecular oxygen and water require a confirmation by an additional independent technique. The best way is to try to detect the corresponding absorption lines by UV-visible spectroscopy. The problem is that sedimentary apatite samples are in the form of non-transparent powder, which is not suitable for optical spectroscopy. The photoacoustic spectroscopy (PAS), which allows measurement of absorption spectra of powdered opaque samples, has been chosen for this purpose (Gaft et al. 1998). PAS works as follows ... 

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