A theoretical analysis of very low energy collision induced vibrational relaxation in the system He–I2 (3Π0u+)

Vibrational deexcitation in the low energy collisions of He with I₂ ${(}^3{\Pi }_{0_u^{+}})$ is examined within the close‐coupled scattering formulation using a sum of pairwise Morse interactions to describe the potential surface. Cross sections for zero total angular momentum are given as a function of energy for various rotational and vibrational transitions with the I₂ molecule prepared in the n=25 vibrational state. Similar results for total angular momentum of 2, 1, and 0 are also reported for the n=1 initial state of I₂. These calculations are in general agreement with the known experimental results and support the arguments advanced previously to explain the unexpectedly large observed relaxation cross section.