Clustering of carbon dioxide around zinc oxide cluster

Highlights: • DFT and QTAIM studies are performed for the adsorption of CO₂ over zinc oxide cluster. • Transfer of electron density occurs from CO₂ to the cage. • Interaction of CO₂ and the cluster extends beyond the first coordination shell. • Critical point analysis suggests weak interaction between adsorbed CO₂ molecules. The clustering and energetics of adsorption of CO₂ on zinc oxide cage are investigated using dispersion corrected density functional theoretical method. The gas molecules are adsorbed over the cage by van der Waals interaction. The interaction energy is increased uniformly until the adsorption of twenty-five molecules of CO₂ which belongs to the first coordination shell of the cage. A correlation between stabilization energy and the molecular electrostatic potential minimum (V_min) indicating that less electron rich nature of oxygens of the cage promotes adsorption of CO₂. Quantum theory of atoms in molecules analysis substantiated weak interactions between the adsorbed CO₂ molecules.