Structural Stability of the Solid Hydrogen Structures by First Principles Under 60~160 GPa

To research the structural stability of the solid hydrogen structures, the thermodynamic and dynamic properties of the solid hydrogen structures of Ⅱ phase P6₃/m, P2₁/c, P6₃/mmc, Pca2₁ and Ⅲ phase C2/c were calculated by first-principles calculations under 60~160 GPa. The results suggest that that only P6₃/m, C2/c and Pca2₁ are competitive structures. The Pca2₁, P6₃/m, and C2/c structures can stably exist in the pressure range 60~78, 78~90 GPa, and 116~160 GPa, respectively.