Physico-chemical characterization of remains from a Bronze Age ochre-burial in Biniadris Cave (Menorca, Spain)

Red ochre pigments have been used since ancient times by many different civilisations on different continents. In the paper presented herein, ten manufactured artefacts and biological materials stained with a red pigment found in the Bronze Age burial site of Biniadris Cave (Menorca, Spain) have been characterised throught X-ray fluorescence, X-ray diffraction, Raman and infrared spectroscopy techniques, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The surface analysis of the bones, hairs and ornaments allowed the chemical composition of the pigment used in the funeral practices and rituals to be unequivocally established as hematite-rich ochre. The finding of a gypsum preparation layer on a sample, below the ochre layer, suggests that it could have been used as a primer before sprinkling with hematite ochre. Given the excellent degree of conservation and the worth of this archaeological record for the study of the symbolic practices in the island of Menorca, these results call for further analyses on a larger set of archaeological artefacts to gain insight into the funeral practices conducted in this cave

Solvent effects on 2-methoxyethanol conformers: an ab initio DFT study using the SCI-PCModel

The four stable conformers of 2-methoxyethanol, CH3O-CH2-CH2-OH (tgg', ggg', ttg and ttt) are studied by ab initio calculations using the SCRF theory and the SCI-PCModel to assess solvent effects on the structure and vibrational spectra of this compound. Full geometry optimizations were carried out at the B3LYP/6-311+G(3df,2df,2p)//B3LYP/6-31G(d) level, and normal mode calculations were performed within the harmonic approximation using the B3LYP/6-31G(d) derived force fields. The solvent, herein represented by a polarizable continuum with a defined dielectric constant, is found to affect significantly the geometry and dipole moment of the individual solute conformers. In addition, the results seem to suggest that the intramolecular H-bond type of interactions, which occur for tgg' and ggg', tend to attenuate the solvent influence. In turn, the conformers which do not exhibit intramolecular H-bond interactions, ttg and ttt, exhibit a stronger solvent influence as revealed mainly by structural and electrostatic changes affecting both the ether O atom and the hydroxyl group.http://www.sciencedirect.com/science/article/B6TGS-40D60M5-3Y/1/80fb3738f5c0f146d020ba40c442d8b

Dynamics of muoniated radical states in phthalocyanines

This work reports a spectroscopic and spin-dynamics [mu]SR study of the positive muon states formed in the phthalocyanines Zn-Pc, H2-Pc and Cu-Pc. In Zn-Pc and H2-Pc, three distinct muoniated radicals are formed, seen to undergo spin-dynamical processes with charge carriers. Two of the states have very similar hyperfine interaction values, and are believed to be due to muon addition at the outer benzene rings. The third one has a significantly lower hyperfine constant, and is tentatively assigned to addition at an inner part of the molecule. In Cu-Pc, the [mu]SR signals found are diamagnetic-like, and the muon seems to be shielded from interactions with charge carriers and local molecular motion.http://www.sciencedirect.com/science/article/B6TVH-4J2M4HS-2/1/fa04f85559a5018a2b46dc076dec98d

Analysis of natural and artificial ultramarine blue pigments using laser induced breakdown and pulsed Raman spectroscopy, statistical analysis and light microscopy

http://www.sciencedirect.com/science/article/B6VNG-4V2NKN2-1/2/88334c7b5f21f6ac19eed9f3f8706b0