Substitution priority of Eu2+ in multi-cation compound Sr0.8Ca0.2Al2Si2O8 and energy transfer
Yang Zhi-Ping, Li Zhen-Ling, Wang Zhi-Jun †, Li Pan-Lai ‡, Tian Miao-Miao, Cheng Jin-Ge, Wang Chao
       

(color online) Schematic illustration of a configurational coordinate diagram of the ground state (Eu2+: 4f75d0), two split excited states (Eu(I) and Eu(II), and showing the energy barrier of the transition Eu(I) state to Eu(II), and showing the energy barrier of the transition Eu(II) state to Eu(I).