Trapping of Freon Gases on Silicon (100)‐2 X 1 Surface: A Density Functional Theory Based Study

ABSTRACT In silico studies of structural properties, energetics as well as spectral bands are carried out to explore the adsorption processes of freon gases, namely, chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs) on the Si(100)‐2 × 1 surface. CFC adsorption over the heterogeneous Si based surface appears endothermic in nature, whereas for HFC adsorption, the process becomes exothermic ( H = −60.59 kcal/mole, −39.83 kcal/mole, and −47.57 kcal/mole for CH 3 F, CH 2 F 2 , and CHF 3 , respectively). On the other hand, Gibbs free energy changes of CFCs and HFCs adsorption reveal endergonic non‐spontaneous nature of the former processes (CFC adsorption) and exergonic spontaneous behavior of the latter processes (HFC adsorption) [ G = −69.60 kcal/mole, −26.89 kcal/mole, and −28.76 kcal/mole for CH 3 F, CH 2 F 2 , and CHF 3 , respectively]. In addition, adsorption process of CH 3 F over the silicon‐based surface reveals lowest activation energy (21.13 kcal/mole, kinetically preferred), most negative (−69.60 kcal/mole, thermodynamically preferred) and most negative binding energy (−40.68 kcal/mole) indicating highly stable adsorbed species. Formation of new bonds as well as lengthening/shortening of the existing bonds are manifested in the infra‐red spectral patterns of the reactants and products.