Accurate calculations of the high-pressure elastic constants based on the first-principles
Wang Chen-Ju†a), Gu Jian-Bing, Kuang Xiao-Yu, Yang Xiang-Dong
       
Pressure dependences of the elastic constants of Ta and Re. Solid symbols represent the elastic constants of C ij obtained when the energy term is considered, and the empty symbols denote the elastic constants of C̄ ij obtained when the energy term is ignored.