A plausible interpretation of the density scaling of the diffusivity in viscous liquids

Fundamental thermodynamic concepts and an earlier elastic solid-state point defect model are employed to formulate an analytical second-order polynomial function describing the density scaling of the diffusion coefficient in viscous liquids. The scaling exponent is correlated, within the approximations made in the present approach, with the pressure derivative of the isothermal bulk modulus. Our findings are compared with computer simulation results.