Soft X-ray induced chemical modification of polysaccharides in vascular plant cell walls

Establishing a molecular relationship between chondritic and cometary organic solids

“…5A (SD2 also exhibits considerable absorption at this energy) consistent with a molecular structure dominated by polyalcohol moieties. Polyalcohols (e.g., carbohydrates and formaldehyde-derived sugars) are highly susceptible to H 2 O elimination yielding ene-ketone moieties (at 286.5 eV), a signature feature of partially degraded polyalcohols (39). The presence of ene-ketone moieties is striking in both formaldehyde polymer samples (F50 and F250; Fig.…”

Dynamic Molecular Structure of Plant Biomass-Derived Black Carbon (Biochar)

“…Further, lignin in coniferous wood (here Ponderosa Pine) is comprised of phenolic monomers derived from coniferyl alcohol, forming a peak at 287 eV which is prominent in the wood spectra (25). However, we also expect a contribution of the mixed 1s-3p/σ* resonance at this energy that correlates with aliphatic C-H. A second common feature associated with aromatic C is a broader band between 292 and 295 eV (1s-σ* resonance) (26).…”

Advances in Using Soft X-Ray Spectroscopy for Measurement of Soil Biogeochemical Processes

“…Once purported as a nondestructive method (Vairavamurthy and Wang, 2002), XANES studies have shown degradation and transformation of some reference compounds through beam exposure over time, particularly when using high photon flux undulator beamlines (Cody et al, 2009;Leinweber et al, 2007;Zubavichus et al, 2004). These problems associated with radiation-induced decomposition also are compounded at soft X-ray energies because X-ray absorption cross sections are higher compared to hard X-ray cross sections.…”