Enhanced quantum size effect in Li and Na clusters via rare gas doping

Albeit its chemical inertness, rare gas doping can substantially enhance the quantum size effect of nanocrystals, yet little attention has been paid on this fascination and the mechanism behind remains unclear. Here, we show that the rare gas dopant breaks bonds of its neighboring atoms, which effects the same to atomic under-coordination on the bond strain, energy quantum entrapment, and valence electron polarization of Li and Na clusters. Consistency between density functional theory calculation and the bond-order-length-strength correlation prediction revealed that the bond strain by 16.86% and 21.12% before and after He doping for Na30 clusters. Observations suggest an effective yet simple means to modulate the physical properties by doping the inert gases.