Computational mining of endohedral C₇₀ electrides: tri-metal alkali and alkaline-earth encapsulation

C₇₀ is the second most abundant fullerene next to C₆₀. In this work, the exploration of C₇₀ based electrides is proposed by theoretical encapsulation of group I/II trimetallic clusters into the C₇₀ cage. Herein, we provide computational evidence that endohedral metallofullerenes M₃@C₇₀ (M = Li, Na, K, Be, Mg, Ca, Sr, Ba) can exist stably by calculating encapsulation energies and analyzing atom centered density matrix propagation molecular dynamics simulations. According to the results of the atoms in molecules analysis, electron localization functions and nonlinear optical properties, M₃@C₇₀ (M = Li, Be, Mg, Ca) fullerenes are identified as electrides. Interestingly, Li₃@C₇₀ and Be₃@C₇₀ are the systems with better electride performances among alkali metal and alkaline earth metal systems, respectively. It is worth noting that C₇₀ can improve the polarizability and first hyperpolarizability of electrides compared with C₆₀. Our work unearths the potential of M₃@C₇₀ electride systems and paves the way for the research of C₇₀-based electrides.