Correlation of the scaling exponent gamma of the diffusivity-density function in viscous liquids with their elastic properties.

Fundamental thermodynamical concepts and a solid-state point defect elastic model are used to formulate a diffusivity-density scaling function for viscous liquids. It is proved in a straightforward manner that the scaling exponent gamma describing the density scaling of the diffusivity is related with the pressure derivative of the isothermal bulk modulus.