  Results from molecular dynamics simulations of two viscous molecular model
liquids -- the Lewis-Wahnstrom model of ortho-terphenyl and an asymmetric
dumbbell model -- are reported. We demonstrate that the liquids have a
``hidden'' approximate scale invariance: Equilibrium potential energy
fluctuations are accurately described by inverse power law (IPL) potentials,
the radial distribution functions are accurately reproduced by the IPL's, and
the radial distribution functions obey the IPL predicted scaling properties to
a good approximation. IPL scaling of the dynamics also applies -- with the
scaling exponent predicted by the equilibrium fluctuations. In contrast, the
equation of state does not obey the IPL scaling. We argue that our results are
general for van der Waals liquids, but do not apply, e.g., for hydrogen-bonded
liquids.
