Elastic Constants of Na and K from Non-parameter Perturbation Calculation

Combined a linear muffin-tin orbital method, which can be used to calculate the total energy and pressure of solids in self-consistent manner, with a generalized elastic energy equation, a non-parameter perturbation method was proposed to compute the elastic constant for cubic metals. The pressure dependence of the shear modulus and bulk modulus for Na and K was calculated. It was found that the computed results agree well with experiments.