The Atomic Structure and Mechanical Properties of ZIF-4 under High Pressure: Ab Initio Calculations.

The effects of pressure on the structural and electronic properties and the ionic configuration of ZIF-4 were investigated through the first-principles method based on the density functional theory. The elastic properties, including the isotropic bulk modulus K , shear modulus G , Young's modulus E, and Poisson's ratio ν of the orthorhombic-type structure ZIF-4 were determined using the Voigt-Reuss-Hill averaging scheme. The results show that the ZIF-4 phase is ductile according to the analysis of K/G and Cauchy pressure. The Debye temperatures obtained from the elastic stiffness constants increase with increasing pressure. Finally, the pressure-dependent behaviors of the density of states and ionic configuration are successfully calculated and discussed.