Adsorption and dissociation of CO₂ on neutral and negatively charged Be_n^m (n = 4, 7, 10, 12, m = 0, -1) clusters

Density functional theory (DFT) is used to optimize the configuration, stability and electronic properties of neutral and negatively charged Be_n^m CO₂ (n = 4, 7, 10, 12, m = 0, -1) clusters. The results show that when CO₂ is adsorbed on the surface of Be_n and Be_n^-1 clusters, the length of C-O bond has different degrees of elongation. In Be₄ CO₂^-1 and Be₁₂ CO₂^-1, a C-O bond of CO₂ molecule breaks naturally (bond elongations reach 134% and 156%, respectively), which is typically dissociative adsorption. Be clusters show better ability to adsorb CO₂ molecules, especially after being negatively charged, its adsorption value increases obviously (about 3.16 eV- -5.965 eV). The analysis of electron properties shows that the orbital energy levels of the corresponding clusters are elevated by negatively charged exciton, so that the orbital hybridization occurs near the Fermi level, thus enhancing the bonding ability of CO₂ molecules with the corresponding clusters. (authors)