Theory of intercollisional interference effects VI: an exactly solvable model exhibiting a shallow interference dip

The theory of intercollisional interference effects developed in earlier publications in this series is applied to a model comprising a Lorentz gas with disks or spheres as the fixed seatterers, and a central induced dipole moment 1/R2ν varying as an inverse power of the intermolecular separation. It is shown that the integrated induced dipole moment [Formula: see text] and the relative dip height 1 – γ can be evaluated analytically and in closed form for this model. The interference dip is relatively shallow owing to a cusp in [Formula: see text] with a maximum where the impact parameter b equals the collision diameter. An asymptotic analysis indicates that the dip actually fills in as ν increases, contrary to earlier expectations. The same analysis is applied with minor modifications to an exponential induced dipole moment, and shows that the interference dip also fills in as the range goes to zero for that system. The applicability of the model to a system with more realistic interactions is discussed.