Restudy of Grüneisen Parameter of Iron in the Pressure Range of 90-160GPa

The Hugoniot equation-of-state (EOS) of porous iron with an average initial density of 6.904g/cm³ has been measured in the pressure range from 90 to 160GPa, and a good straight fitting D = 2.997+1.603μ has accordingly been obtained, where D is the shock wave velocity and μ the particle velocity, both in units of km/s. Combining this with the Hugoniot EOS of non-porous iron, the Grüneisen EOS and the Rankine-Hugoniot energy conservation relation, and taking the possible solid--liquid transition correction, we have calculated the Grüneisen parameter γ of iron and obtained the γ₀ρ₀ = γρ =const, with γ₀ = 1.945 and ρ₀ = 7.856cm³, ρ being the density.