Quantum Interference Induced from the Λ Split of Π State Diatom

To interpret theoretically the abnormal phenomenon in the experiment of collision-induced rotational energy transfer of CO（A1Π，v=3）with He by Sun et al.，the time dependent first order Born approximation，and the long-range interaction potentials and“straight-line”trajectory approximation are taken into account. A theoretical model of quantum interference of Π-state diatomic molecules，which originates from the difference between the two "Λ-related collision potential energy surface，is presented. The abnormal phenomenon of σε→ε'ΔJ=0<σε→ε'ΔJ=±1 for He is also interpreted successfully. At first the theoretical development of collision-induced quantum interference on rotational energy transfer is reported；then a theoretical model of quantum interference of Π-state diatomic molecules，which originates from the difference between the two "Λ-related collision potential energy surfaces，is presented；in the end the results have been discussed and concluded.