Structure and properties of subnanosized magnesium clusters at correlated ab initio levels

The structures of the full set of isomers of subnanosized magnesium clusters Mg2-Mg10, previously found through a long-term global search at the DFT level, were studied by optimisation and calculation of vibrational frequencies at the correlated ab intio levels up to MP2/cc-pVQZ and CCSD(T)/cc-pVQZ. For the full set of isomers, a genealogical scheme for clusters Mg2-Mg10 was constructed. When calculated at the ab initio level, the correlation between the relative energy of an isomer and its isotropic electrostatic polarizability previously discovered at DFT level is fulfilled, even when the isomer structures or their energy ordering are different. This finding is in agreement with the previously formulated principle of maximum tightness of electronic shell, which can be used to explain cluster stability. To assess the possibility of structure-selective cluster synthesis, the relative content of isomers under equilibrium conditions was estimated. Using these data, the possibility of the structure-selective synthesis of cluster isomers is discussed.