Bader Charges Of Atoms Research Articles

A computational study of the interaction of oxygenates with the surface of rutile TiO2(110). Structural and electronic trends

A variety of OH containing molecules in their different modes of adsorption onto the rutile TiO2(110) are studied by means of density functional theory. A special focus is given to ethanol, ethylene glycol and glycerol. The different species were analyzed with respect to the adsorption energy, work function, and atomic Bader charges. Our results show that dissociated adsorption is favored in all cases. Within these modes, the strongest binding is observed in the case of bidentate fully dissociated adsorption, followed by bidentate partially dissociated then the monodentate dissociated modes. The dependence is also noted upon charge transfer analysis. Species adsorbing with two dissociated OH groups show a negative charge which is roughly twice as large compared to those exhibiting only one dissociated group. In the case of molecular adsorption, we find a small positive charge on the adsorbate. The change in work functions obtained is found to be negative in all studied cases. We observe a trend of the work function change being more negative for glycerol (3 OH groups) followed by ethylene glycol (2 OH groups) and the remaining alcohols (1 OH group), thus indicating that the number of OH groups present is an important factor in regards to work function changes. For the complete series of adsorbates studied (methanol, ethanol, isopropanol, ethylene glycol, glycerol, hydrogen peroxide and formic acid) there is a linear relationship between the change in the work function and the adsorption energy for the molecular adsorption mode. The relationship is less pronounced for the dissociated adsorption mode for the same series.

Germanene on Al(111): Interface Electronic States and Charge Transfer

The electronic structure of germanene is investigated by high resolution photoemission and density functional theory calculations. The core level Al 2p and Ge 3d lines are measured on germanene grown on Al(111) by using synchrotron radiation. The Ge 3d line is shifted toward the low binding energies with respect to bulk Ge, and shows three components, reflecting the sites multiplicity of the germanene atomic structure. The calculations reveal a sizable charge localization at the germanene/Al(111) interface, a charge transfer from the Al surface atoms to the germanene, and the existence of three nonequivalent Ge sites with three different atomic Bader charges, in agreement with the photoemission measurements.