Papers by Keyword: Molecules

Abstract: Investigators used Potentiodynamic Polarization, Spectroscopy of Electrochemical Impedance (EIS), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX), Spectroscopy of X-Ray Photoelectron (XPS), and chemical studies to examine the inhibitory effect of Theobroma cacao peel extract (TCPE) on mild steel (MS) corrosion in 1.5M HCl. Studies of electrochemical data indicate that, TCPE reduces MS corrosion through adsorption using a mixed inhibition mechanism. As the inhibitor concentration grows and temperatures lowers, TCPE becomes more protective. The adsorption of TCPE molecules on the MS surface is controlled by the Langmuir adsorption isotherm. To determine the correlation between the hampers effect and the structure of TCPE molecular, a number of chemical characteristics were computed.

Abstract: Calculations of gamma spectra for positron annihilation for a selection of molecules, including methane and its fluoro-substitutes, ethane, propane, butane and benzene are presented. The contribution to the -spectra from individual molecular orbitals is obtained from electron momentum distributions calculated using the density functional theory (DFT) based B3LYP/TZVP model. For positrons thermalised to room temperature, the calculation, in its simplest form, effectively treats the positron as a plane wave and gives positron annihilation  spectra linewidths that are broader (30–40%) than experiment, although the main chemical trends are reproduced. The main physical reason for this is the neglect of positron repulsion from the nuclei. We show that this effect can be incorporated through momentum-dependent correction factors, determined from positron-atom calculations, e.g., many-body perturbation theory. Inclusion of these factors in the calculation gives linewidths that are in improved agreement with experiment.