Thermal desorption of chiral molecules from a nanostructured chiral surface: Insights from computer simulations

Temperature programmed desorption (TPD) of model chiral molecules from a chiral surface with periodic pattern of active sites was studied theoretically using the Monte Carlo method. The simulations were performed for enantiomerically pure and racemic layers adsorbed on the chiral surface with an ordered (5×5)R27∘ superstructure of the active sites. It was demonstrated that an efficient separation of the enantiomers on the nanostructured surface could be achieved by suitable manipulating energetic properties of the surface. Moreover, the influence of factors such as lateral interactions in the adsorbed phase and mobility of the adsorbed molecules on the desorption kinetics was examined. The obtained results provided some insights into the mechanism of chiral selection with nanostructured surfaces under ultra high vacuum conditions. In particular, it was demonstrated that effectiveness of the separation decreases with coverage due to reduced chances for the enantiomers to occupy their energetically preferred clusters of adsorption sites.