Evaluation of aluminum critical point using an ab initio variational approach

We present a method to evaluate the critical point of aluminum using a variational approach based on the ab initio molecular-dynamics code CPMD. We found that the critical density, temperature, and pressure are equal to 0.44 g/cm(3), 7963 K, and 0.35 GPa, respectively. At the critical point, the system is rarefied, coupled, and degenerate. The shear-viscosity and the self-diffusion were estimated at the critical point. Using the Kubo-Greenwood formula, we obtained the electrical conductivity, the absorption coefficient, the index of refraction, and the reflectivity at the critical point. We followed Mott's ideas to study the metal-nonmetal transition related to the critical point. Our method can be useful to investigate phase transition and the critical point of metals.