A relativistic DFT study on the structure and property of M(M=Ba, Sr) @ C74 (D 3h).

Highlights: [•] Three equivalent isomers, with Ba or Sr located about 1.7Å off-center. [•] The energy barriers for Ba and Sr movement in C₇₄ are 8.30 and 7.88kcalmol⁻¹. [•] M@C₇₄ (M=Ba, Sr) degenerate from D _3h to C _2v when Ba or Sr was encapsulated. [•] The NMR spectrum of La@C₇₄ according to the trajectory was predicted. [•] Blue-shift of Raman mode was interpreted, in agreement with the experiments. [ABSTRACT FROM AUTHOR]