Abstract: Collisional quantum interference (CQI) on rotational energy transfer was observed by Sha et al.(J. Chem.Phys., 1995, 102：2772) in static cell, and the integral interference angle which determines the magnitudes of the transition cross sections was measured. To obtain more precise information, the experiment in the molecular beam should be taken, as the integral interference angle is the average effect of the differential interference angle. Thedifferential interference angle of Λ-Related Quantum Interference of ¹Π-state diatom was presented to measure the degree of coherence, by using the first order Born approximation of time-dependent perturbation theory. The anisotropic Lennard-Jones interaction potential is employed to simulate their interference angles. The relationships of the differential interference angle versus the factors of the experiment in the molecular beam, including experimental temperature, partners, the distance of the interaction and rotational quantum number, are obtained. And the various factors that influen ce the interference angles are discussed. This theoretical model is important to understand orperformin the experiment of the molecular beam.

Key words: Quantuminterference, Collision-induced rotational energy