It was found that both the diffusion activation energy Ea(D) and Ea(Sex) increased linearly with pressure and had the same slope 0.022eV/GPa) for liquid Al. The temperature and pressure dependence of excess entropy was well fitted by the expression-Sex(T,P)/k = a(P) + b(P)T + c(P)exp(Ef/kT), which together with the small ratio of Ef/kT led to the relationship of excess entropy to temperature and pressure, i.e. Sex ≃ -cEf/T, where c was about 12 and Ef (= ΔE-PΔV) was the favorable energy. Therefore, there existed a simple relationship between Ea(Sex) and Ef, i.e. Ea(Sex) ≃ cEf.

Diffusion Activation Energy Versus the Favourable Energy in Two-Order-Parameter Model: a Molecular Dynamics Study of Liquid Al. Li, Y.D., Hao, Q.H., Cao, Q.L., Liu, C.S.: Chinese Physics B, 2010, 19[8], 086104