Effect of confinement and external mechanical force on the cleavage of the bond in a diatomic molecule

Abstract

Mechanochemical synthesis has gained much attention owing to its environment-friendly nature. The application of mechanical force on the reactants changes the reactivity of the chemical systems and the reactivity of the chemical entities can be changed by altering its surrounding, like encapsulating the chemical entities inside a cavity. The effect of confinement and mechanical stretching force on the nature of the bond in the diatomic systems has been extensively studied using theoretical models. The diatomic systems that have been considered are F2, H2, O2, N2, ClBr, NaCl, CO, LiF and HCl and the confinement being used is that of fullerene cage C60. It has been found that the confinement strengthens the diatomic bond for ClBr, NaCl, N2 and H2 systems whereas for some other systems, the bond strength decreases. The possible reason behind such observation has been explored with the help of Natural Bond Orbital (NBO) analysis, Atoms in Molecules (AIM) analysis and Energy Decomposition Analysis (EDA). The reactivity change with respect to the external mechanical stretching force has been studied and the presence of non-covalent interaction (NCI) is visualised through NCI plots. The dynamics of the systems have also been explored using Atom Centred Density Matrix propagation (ADMP) simulation.