  A density scaled diffusivity function for viscous liquids derived earlier
[Phys. Rev. E 79, 032501 (2009)] is revisited, based on an improved equation of
state assuming that the isothermal bulk modulus increases linearly with
pressure. Without making any assumption on the interconnection between the
scaling exponent and the Gruneisen parameter, we prove that the scaling
exponent is identical with the pressure derivative of the isothermal bulk
modulus. We further discuss probable interconnection between the scaling
exponent and the Gruneisen parameter.meter.
