The structure of the adsorbate systems formed by mercaptobenzothiazole (MBT) and analogue molecules on the CdS(101 h0) surface is studied quantum-chemically using density functional theory. Preliminary calculations of the free adsorptive molecules indicate an energetic preference of their thione form compared to the thiol form. For the anions of the adsorptive molecules, the role of the endocyclic nitrogen and the exocyclic sulfur as possible donor atoms is examined by means of known chelate complexes. Clusters with 24 and 28 atoms that are saturated by point charges have been developed as surface models. Geometry optimizations show that the structure of the adsorbate systems is dominated by the formation of two coordinative bonds from the donor atoms of the adsorptive anions to two adjacent cadmium atoms of the surface. It results that the molecular plane of the adsorptives is tilted with respect to the normal of the crystal face. The calculated tilt angle for the MBT adsorbate agrees with angle-dependent XANES measurements, the only structural information presently available from experiment. It is found that the tilt angle changes with the variation of the heteroatom in the five-membered ring of the adsorptives. The molecule-surface interactions leading to these structural differences are analyzed. Further, the relaxation of the surface is included in the investigation. It becomes obvious that the direction of the relaxation of the free surface is reversed by the formation of the adsorbate bonds.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.