Density functional investigations for geometric and electronic properties of In₄M and In₁₂M (M = C, Si, In) clusters

First-principle calculations are performed to study geometric and electronic properties of both neutral and anionic In_4M and In_12M (M = C, Si, In) clusters. In_4C and In_4Si are found to be tetrahedral molecules. The icosahedral structure is found to be unfavourable for In_12M. The most stable structure for In_12C is a distorted buckled biplanar structure while for In_12Si it is of an In-cage with the Si located in the centre. Charge effect on the structure of In_12M is discussed. In_4C has a significantly large binding energy and an energy gap between the highest-occupied molecular-orbital level and the lowest unoccupied molecular-orbital level, a low electron affinity, and a high ionization potential, which are the characters of a magic cluster, enriching the family of doped-group-IIIA metal clusters for cluster-assembled materials.