ABSTRACT Slavíkite, (H 3 O + ) 3 Mg 6 Fe 15 (SO 4 ) 21 (OH) 18 · 98H 2 O, is a rare and structurally complex secondary sulfate occurring in sulfide‐weathering zones and acid mine drainage environments. We present a detailed vibrational spectroscopic study of slavíkite from its type locality at Valachov Hill and two additional occurrences in the Czech Republic using Raman spectroscopy, complemented by Fourier‐transform infrared spectroscopy, powder X‐ray diffraction, and electron probe microanalysis. Raman spectra are characterized by three intense bands in the sulfate ν ₁ stretching region at 988, 1010, and 1033 cm −1 . A pronounced orientation dependence of Raman band intensities was identified as a critical factor affecting spectral interpretation and potentially leading to the misidentification of slavíkite as mixed sulfate assemblages. Despite minor Al substitution detected in all studied samples, Raman and FTIR spectra from different localities and specimens collected over a period of nearly four decades show only negligible differences, indicating long‐term preservation of the mineral structure under ambient conditions. Thermo‐Raman experiments reveal stability up to ~60°C, followed by progressive dehydration and structural collapse above 70°C, completing above ~330°C. Heating to 600°C results in the formation of stable products of hematite and anhydrous Mg‐sulfates. The dataset provides a robust reference for slavíkite identification and improves understanding of its structural stability and transformation pathways in complex sulfate assemblages.
ABSTRACT This study presents a comprehensive nondestructive technical analysis of two late 16th‐century landscape miniatures from the Princes Czartoryski Collection at the National Museum in Krakow. The works, created by Hans Bol (1584) and his pupil Jacob Savery (1590), were examined to characterize the masters' techniques, pigment palettes, and the extent of historical conservation interventions. A multianalytical approach was employed, integrating multiband imaging (MBI), scanning macro‐XRF (MA‐XRF) imaging, Raman spectroscopy (RS), and reflectance imaging spectroscopy (RIS). The results revealed that the two miniatures evaluated underwent historical retouching, primarily in the sky areas, identified through UV imaging. The primary palette consists of copper‐based greens (brochantite and posnjakite) and blues (azurite), with the notable presence of “flower of indigo” in dark grey areas. Red hues were achieved using cinnabar, cochineal, and hematite, the latter being the primary pigment for architectural elements in Bol's work. The study demonstrates the high technical quality of the miniatures and highlights the complementary nature of the applied spectroscopic techniques in identifying complex pigment mixtures and preparatory underdrawings without the need for sampling.
ABSTRACT The fast growth of semiconductor and low dimensional materials has created a necessity for robust characterization approaches to study their structural and electrical properties. The most popular tool for this goal is the Raman spectroscopy however the asymmetric shape of Raman lines is often observed due to the phonon confinement and the Fano interference which makes their interpretation difficult. Here, a user‐friendly web‐based computational platform is proposed that combines the phonon confinement, Fano, and combination Fano‐confinement models for automated Raman line‐shape analysis. The software allows users to submit Raman spectra and get quantitative analysis, model comparison, and parameter extraction with a single click. The software democratizes advanced Raman analysis to non‐expert users who do not have programming or theoretical experience. The framework was tested on Raman spectra with dominating confinement, dominant Fano interaction, their coexistence and on published silicon nanocrystal data, providing crystallite sizes compatible with reported studies. Future versions will incorporate a comprehensive multi‐material database for intelligent material identification and rapid spectral interpretation for next‐generation Raman spectroscopy.
ABSTRACT In Flanders, painted burial tombs are a distinctive funerary practice between the 13th and 17th centuries, mainly located in Bruges and the Zwin region. These brick‐built graves, often single or double structured, were plastered and painted on the inside with religious depictions intended to guide the deceased in the afterlife. They were typically reserved for elite individuals such as clergy and nobility. Despite numerous archaeological finds, these tombs and their decorations remain under‐researched. To address this gap, the present study examines three painted tombs that were excavated at the former Eekhout Abbey in Bruges using Raman spectroscopy for pigment and material characterization. Initially, in situ measurements were performed with mobile Raman instrumentation to obtain a general overview of the materials used. When performing mobile Raman measurements, the red pigments were easily identified as haematite and vermilion. However, other coloured regions (e.g., yellow, black, grey and blue) proved to be more challenging to identify during the in situ measurements. Therefore, samples were collected for further analysis with a benchtop micro‐Raman system. This analysis identified carbon black and goethite for respectively the black‐ and yellow‐coloured regions and unexpectedly revealed the use of indigo as a blue pigment. Additionally, traces of an arsenic‐based pigment were detected, though it remains uncertain whether these were intentionally applied or are the result of contamination.
Uranium dioxide (UO2) supports the incorporation of oxygen into the fluorite space group up to UO2.25. The precise stoichiometry of UO is determinable via Raman spectroscopy. Here, we present methods to use Raman spectroscopy to determine the stoichiometry of the intermediate calcination products between UO2 and U3O8 via analysis of a series of U3O samples. Unlike UO2, U3O8 does not appear to support intermediate phases between . Instead, we show that the stoichiometry of intermediate compounds can be determined by monitoring the ratios of the UO2 and 2LO Raman peaks to the primary peak at 430 cm-1 in U3O8 or by analyzing the spectral variability across a sufficiently large sample of point spectra. Determining the stoichiometry of incompletely oxidized U3O8 using microspectroscopy methods has applications in nuclear forensics, material aging, and fuel monitoring.
