The N-state semiclassical approach is used in the calculation of vibrational transition probabilities for atom-Morse-oscillator collinear collisions. Exact semiclassical calculations for several initial classical phases are compared with rigid-body results. The transition probabilities are found to be strongly dependent upon the initial phase. Two procedures are used for matching the Morse potential to a quadratic potential. The resulting transition probabilities indicate that the potentials should be matched on their repulsive sides rather than at their minima.