Theoretical study of the correlation between the infrared intensity spectrum and the geometric structure of sodium nanoclusters in the framework of density functional theory

In this article, a theoretical study has been done using quantum calculations in the framework of density functional theory on the stability of structures, electronic properties and vibrational frequencies of sodium nanoclusters Na_n (n=10-48). By calculating the coordination number, it was determined that the first motif that is created and repeated in these nanoclusters is an icosahedron, and as the number of atoms increases, the number of these icosahedra is also increased. The second difference of energy and the gap between the last occupied level and the first unoccupied level show that the more stable nanoclusters have an even number of electrons and also have a more spherical shape than the rest of them. The two sharp peaks in the second difference of energy diagram are related to Na_20 and Na_40 respectively, which indicate the greater stability of these two nanoclusters compared to the others and also match the magic numbers.In terms of geometrical shape, the nanoclusters were divided into 4 categories using the shape deformation parameter, and their correlation and relationship with the infrared intensity spectrum was investigated