Sulfates on Mars: A systematic Raman spectroscopic study of hydration states of magnesium sulfates

Chemistry of Frozen Sodium–magnesium–sulfate–chloride Brines: Implications for Surface Expression of Europa’s Ocean Composition

“…In comparing the spectrum of the frozen brine (blue) with the controls (Figure 2), we assign the sulfate υ 1 symmetric stretching mode at 990 cm −1 to mirabilite (Hamilton & Menzies 2010), as no known hydrated salts containing MgSO 4 exhibits a peak at this position (Wang et al 2006). Further evidence for the formation of mirabilite can also be seen in the O-H stretch region, specifically with the shoulder at 3345 cm −1 (orange dotted line).…”

“…Raman spectroscopy is a particularly suitable probe for this task due to its fast timescales and sensitivity of vibrational modes toward different chemical environments. Moreover, Raman data on individual salts are readily available in the literature (Hibben 1937;Capwell 1972;Samson & Walker 2000;Wang et al 2006;Hamilton & Menzies 2010), facilitating the characterization of our samples. The Raman instrument is also equipped with an Olympus BXFM 50× objective, allowing for continuous optical observation of the sample during each experiment.…”

Molecular dynamics study on thermal dehydration process of epsomite (MgSO4·7H2O)

“…The periodic peaks of the crystalline structure are no longer evident under the rapid loss of water, which is possibly due to the collapse of the crystal framework and formation of amorphous phases. [7,8] However, a rough symmetry around the central plane is still existent. (c) The two peaks in the MgSO 4 density grow higher and begin to move towards the centre.…”

“…The higher diffusion rates of the surfaces come from the breakdown of the hydrogenbonding network [32] and the collapse of the lattice frameworks. [7,8] The slow diffusion kinetics in the centre region seems to limit the dehydration rate and, therefore, the dehydration process can be characterised as a diffusion-driven process. In the n ¼ 2.0 plot in Figure 8(b), D z is no longer evidently larger in the surface regions but approximately shows a constant value.…”

Raman Hyperspectral Imaging of Microfossils: Potential Pitfalls

“…By the end of 1978, the 50 th anniversary of Raman's discovery, 24,000 papers dealing with various kinds of Raman effect had been published. Raman spectroscopy is becoming increasingly popular in geoscience applications, as astrobiologists, geologists, paleontologists, and planetary and space scientists discover the wealth of nondestructive mineral and organic molecule/macromolecule data that Raman spectroscopy can afford (e.g., Bény, 1992, 1999;Wopenka and Pasteris, 1993;Beyssac et al, 2002;Wang et al, 2004Wang et al, , 2006Marshall et al, 2010Olcott Marshall et al, 2012aEdwards et al, 2013).…”