  This paper deals with the treatment of quantum interferences in the
semiclassical initial value theory of rotationally inelastic scattering in the
interaction picture [C. W. McCurdy and W. H. Miller, J. Chem. Phys. 67, 463
(1977)]. It is shown that substituting the original phase index by a new one
extends the range of applicability of the theory. The resulting predictions are
in close agreement with exact quantum scattering results for a model of
atom-rigid diatom collision involving strong interferences. The developments
are performed within the framework of the planar rotor model, but they are
readily applicable to the three-dimensional case.
