Electron counting rules for transition metal-doped Si12 clusters

- PSM and pELI-D allow counting of delocalized electrons for a doped Si cluster.
- 2Dz2 orbital of Si12Cr is left empty due to the splitting of 2D shell in D6h symmetry.
- The enhanced stability of Si12Cr is due to the 16-electron shell closure.
- The enhanced stability of Si12Fe is due to the 18-electron shell closure.
- Gradual variation in the stability of Si12M is related to their electronic structures.