Adatoms, Defects, and Kink Edges

Atoms with even fewer neighbors perform both atomic like and bulk like associated with shorter and stronger interatomic bonds. The bond contraction raises the local charge and energy density and the bond strength gain deepens the local potential well and entraps the core electrons. The locally and densely entrapped core electrons in turn polarize the valence electrons. The subjective valence electron polarization occurs to those atoms with unpaired lone electrons in the s orbitals such as Rh, Au, Ag, Cu and the unpaired 4f145d46s2 (5d56s1 seems to be stable) electrons of the W adatoms and Mo(4d55s1) as well. However, the Co(3d74s2) with fully-occupied s electrons and the Re(5d56s2) with semi-occupied d electrons exhibit entrapment dominance. The undercoordination resolved valence electron entrapment or polarization laid foundations for the extraordinary catalytic ability of the excessively undercoordinated atoms and the dispersed single atom.