Theoretical investigation of X₁₂O₁₂ (X = Be, Mg, and Ca) in sensing CH₂N₂: A DFT study

The feasibility of detecting diazomethane (CH₂N₂) in the gas phase by adsorption onto the exterior surface of inorganic-based X₁₂O₁₂ (where X can be Be, Mg, or Ca) nanocages is investigated here using DFT. All the structures, including those of the pristine CH₂N₂ and of the nanocages, as well as of the CH₂N₂/nanocage systems, have been optimized using the B3LYP-D3, M06-2X, ωB97XD, and CAM-B3LYP functionals, in conjunction with 6-311G(d) basis set. NBO, NCI, and QTAIM analyses results are in good agreement with each other. Furthermore, the Density Of States (DOSs), the natural charges, the Wiberg Bond Indices (WBI), and natural electron configurations were considered to investigate the nature of intermolecular interactions. The energy calculations indicate a strong size-dependent adsorption, with the nanocages comprised of large atoms being able to attract CH₂N₂ more strongly, and hence bind with it more effectively. The adsorption incurs also significant changes to HOMO and LUMO energies.