Photoluminescence properties of gypsum

Abstract

The photoluminescence (PL) properties of four gypsums from three localities, namely, Inner Mongolia (China), Turkey, and Canada, are investigated at room temperature. Under 365 -nm excitation, two types of gypsums from Inner Mongolia exhibit different luminescence colors, namely, yellow and cyan -white, and gypsums from Turkey and Canada exhibit yellow and bluish -white luminescence, respectively. The PL spectra of these gypsums consist of continuous sub -bands distributed in all visible wavelengths, and the excitation spectra of these gypsums consist of continuous sub -bands distributed in a wide range of wavelengths, i.e., 200 -500 nm. The features of PL and excitation spectra suggest that the origin of luminescence from these gypsums may be luminescent organic substances included into crystals in the growth process rather than the impurity ions substituted for Ca 2+ .

Luminescence spectra of chabazite-Ca, a zeolite mineral

“…2. Taga et al (2011) proposed that the cause of the bluish-white luminescence from selenite is luminescence from the inclusion of organic molecules such as aromatic hydrocarbons. On the other hand, many researchers have investigated the excitation-emission matrix profiles of aquatic fulvic acids in natural waters from streams, rivers, lakes and oceans (Coble et al 1990;Coble 1996;McKnight et al 2001;Westerhoff et al 2001).…”

“…This feature of the PL spectrum is characteristic of luminescence from organic molecules (Gorobets and Rogojine 2002). Taga et al (2011) reported on the PL properties of four gypsum samples from three localities. The PL emission and excitation spectra of selenite from Alberta, Canada, which is famous for the hourglass pattern under UV light excitation, are quite similar to those shown in Fig.…”

Comparative Raman spectroscopy of astrobiology relevant bio‐samples and planetary surface analogs under UV–VIS–IR excitation

“…Several of luminescent atoms often contributing to PL are placed (most right column) at around their resonant excitation energies. 14 Data for absorption/PL are taken: for amorphous carbon-from Shang et al 59 ; for gypsum-Taga et al 60 ; for olivine-Rossman and Ehlmann 61 , for hematite-Zangeneh et al 62 F I G U R E 7 Examples of original (untreated) UV-VIS-NIR-IR Raman spectra taken at different locations on the S-MRS simulant samples. Photon flux  integration time  number of averages are @ 325 nm: 3.2Á10 15 μm À2 s À1  10 s  10; @ 532 nm: 4.4Á10 15 μm À2 s À1  1 s  900; @ 785 nm: 3.4Á10 16 μm À2 s À1  10 s  10; @ 1064 nm: 3.2Á10 13 μm À2 s À1  180 s  1.…”

“…Gypsum is classified as a fluorescent mineral owing a broad PL spectrum in the VIS range peaked in orange-yellow under UV excitation. 60 The IR Raman response is free of a PL background but also does not return a reasonable Raman spectrum. Thus, IR Raman occurs to be not very useful for determination of gypsum in such a complex "regolith" due to both lower Raman efficiency and strong matrix effect.…”

Characterizing the Intrinsic Fluorescence Properties of Historical Painting Materials: The Case Study of a Sixteenth-Century Mesoamerican Manuscript

“…21,22 The gypsum that is used in the preparation layer is another possible fluorophore, but its emission (associated to the presence of inclusions) is centered at higher wavelengths (around 650 nm) than what was found on the Codex substrate. 23 Finally, the organic binder probably present in the gypsum preparation could also be emitting.…”