  Fundamental thermodynamics and an earlier elastic solid-state point defect
model [P. Varotsos and K. Alexopoulos, Phys. Rev B 15, 4111 (1977); 18, 2683
(1978)] are employed to formulate an analytical second-order polynomial
function describing the density scaling of the diffusion coefficient in viscous
liquids. The function parameters are merely determined by the scaling exponent,
which is directly connected with the Gruneisen constant. Density scaling
diffusion coefficient isotherms obtained at different pressures collapse on a
unique master curve, in agreement with recent computer simulation results of
Lennard-Jones viscous liquids, [D. Coslovich and C.M. Roland, J. Phys. Chem. B
112, 1329 (2008)].
