Electron collisions with α-D-glucose and β-D-glucose monomers

摘要

The development of new alternative routes for production of second generation ethanol fromsugarcane biomass poses a challenge to the scientific community. Current research in this fieldaddresses the use of a plasma-based pretreatment of the lignocellulosic raw material. With the aimto provide a theoretical background for this experimental technique we investigate the role oflow-energy electrons from the plasma in the rupture of the matrix of cellulosic chains. In this paper,we report calculated cross sections for elastic scattering of low-energy electrons by the α- andβ-D-glucose monomers. The calculations employed the Schwinger multichannel method withpseudopotentials and were carried out at the static-exchange and static-exchange plus polarizationlevels of approximation. Through the comparison of the results obtained with inclusion ofpolarization effects we discuss the influence of the different conformations of the hydroxyl grouplinked to the anomeric carbon on the resonance spectra of these molecules. Resonant structuresappearing at different energies for α- and β-glucose at the low-energy regime of impact energies canbe understood as a fingerprint of an "isomeric effect" and suggest that distinct fragmentationmechanisms proceeding via σ~*shape resonances may become operative depending on the glucoseanomer under consideration. For energies above 15 eV the integral elastic cross sections are verysimilar for both monomers. Differential cross sections for the glucopyranose anomers considered inthis work are typically dominated by a strong forward scattering due to the molecules' large electricdipole moments and, for energies close to the resonances' positions, they display particular featuresat the intermediate angular region, notably a pronounced f-wave scattering pattern, that are probablyassociated with the presence of those structures.