Cover Image

Abstract

The cover image is based on the Research Article Raman band widths of anhydrite II reveal the burning history of high‐fired medieval gypsum mortars by Thomas Schmid et al., https://doi.org/10.1002/jrs.5632.

Recent advances in linear and nonlinear Raman spectroscopy. Part XIV

“…They were able to fill the gaps in the literature and give the correct identification of aphthitalite and thenardite even when secondary bands were not observed. Schmid et al [133] found that the Raman band widths of anhydrite II reveal the burning history of high-fired medieval gypsum mortars. Sodo et al [134] employed Raman and time of flight secondary ion mass spectrometry to answers specific conservation questions regarding Bosch painting of Saint Wilgefortis Triptych.…”

Shedding light onto the spectra of lime—Part 2: Raman spectra of Ca and Mg carbonates and the role of d‐block element luminescence

“…In the predecessor paper to this article, we described a red luminescence emission consisting of several sharp lines (thus, in some other studies confused with Raman bands), which within the phases of the lime cycle was assigned to burnt lime (calcium oxide, CaO), because the effect was lost upon slaking to calcium hydroxide and not restored during carbonation to calcium carbonate. [1] Due to its specificity, this luminescence effect was employed for mapping the distribution of Raman-inactive free lime CaO in the microspectroscopic imaging of a 19th-century Portland cement mortar sample, [2] but the reason for the emission was not known so far. A literature survey yields foreign element ions, fluorescing point defects (F centres) and radical ions (e.g., O -• ) in the crystal lattice as possible reasons.…”

“…A literature survey yields foreign element ions, fluorescing point defects (F centres) and radical ions (e.g., O -• ) in the crystal lattice as possible reasons. [1] Because often, rare earth (f-block) elements are mentioned in the discussion of luminescence in inorganic phases, we would like to emphasise the possibility of dblock element ions in a crystal field as potential reason and give the Raman community a better understanding of the according theoretical background. In our predecessor study, rare earth element ions were considered unlikely as fluorophores, because of the reproducibility of the observed spectral pattern requiring that always the same of these easily interchangeable elements would have to be present in CaO.…”

“…In our predecessor study, rare earth element ions were considered unlikely as fluorophores, because of the reproducibility of the observed spectral pattern requiring that always the same of these easily interchangeable elements would have to be present in CaO. [1] A narrowband luminescence emission caused by Cr 3+ ions integrated in the crystal lattice of MgO-close chemical relative of CaOwas described by Otto Deutschbein in 1932, [3] followed by studies investigating either the sharp central band and features closely nearby [4][5][6] or the full spectral pattern including satellite bands around the central feature. [7][8][9] Anastasia Chopelas described the theoretical background of this effect in detail.…”

“…Comparison of the latter enables the elucidation of the source of the previously described red lime luminescence. [1] A survey of basic principles of this effect is aimed to sharpen the awareness and provide strategies for the identification and assignment of narrowband fluorescence effects in the Raman community, where mainly the ruby luminescence emitted by Al 2 O 3 :Cr 3+ seems to be relatively widely known. Perhaps, the present study can similarly bridge the fields of Raman scattering and luminescence emission like the pioneering study on ruby by Rappal S. Krishnan.…”