Adsorption of CH_2CHF on the Anatase (101) Surface: A Quantum-Mechanical Study

摘要

The adsorption of CH_2CHF on the anatase (101) surface has been studied by a periodic approach using hybrid-exchange density functional theory. The simulation was performed on the basis of a recently proposed experimental model for vinyl fluoride and chloride describing the adsorption of CH_2CHX through the halogen atom rather than the C=C double bond according to the infrared spectra. The adsorption has been investigated using different surface coverages and periodicities, and the energetics have been considered in terms of interaction, distortion, and binding energies. A simple model of nearest and next-nearest neighbors has been adopted to obtain the energies in the limit of an isolated adsorbed molecule and to quantify the lateral effects. The adsorbate-substrate interaction for the anatase surface resulted weaker than that for the rutile (110) one. The vibrational frequencies of the adsorbed molecule have been computed and found in agreement with the experimental ones thus supporting previous infrared interpretations.