Analytical models of the invariants (trace and anisotropy) of the diatom polarizability tensor are formulated that differ from existing models by the suppression of the classical long-range components at close range ("damping"). Such damping is imperative in diatomic systems where the long-range polarizability terms are relatively large and/or the collision energies are high so that substantial penetration of the electronic shells of the colliding atoms takes place, e.g., for collision-induced light scattering by mercury vapor at high temperatures. When a small number of physically meaningful parameters of the polarizability models are properly adjusted, the binary trace and anisotropy collision-induced spectra of mercury vapor are closely reproduced from theory in all details. An improved model. of the Hg-Hg interaction potential, which reproduces the existing : bound mercury dimer slates as well as the viscosity data, includes a similar damping term fur suppression of the dispersion part at close range.