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We have investigated collision induced rotational and vibrational energy transfer in the Li2 A1Σu+(vi,ji=30)−Ne system experimentally under single‐collision conditions at an effective temperature of 691 K. Over 800 inelastic rate constants have been measured, with the initial vibrational level vi ranging from 2 to 24 and −2≤Δv≤+2. Increasing vi results in a linear increase in the vibrational transition rate constants, which is accompanied by a decrease in the rotationally inelastic transition rate constant. The total inelastic rate constant increases with vi only at the highest values of vi. Net vibrational energy transfer 〈ΔE〉 calculated using rotationally summed rate constants is qualitatively consistent with a simple model. However, explicit inclusion of rotation gives quite different values of 〈ΔE〉. The experimental results are compared with our three‐dimensional trajectory calculations on an ab initio potential surface and on a simple repulsive potential surface.

We report measurements of level‐resolved rate constants for inelastic scattering in the Li2 A 1Σ+u–Ne system, with initial molecular quantum numbers vi=2 and ji=30. The measurements include rotationally and vibrationally inelastic rate constants with ‖Δv‖≤2. Comparison is made with rate constants computed from classical trajectories on a recently reported ab initio potential energy surface. Our work constitutes the first comparison between experiment and calculation on an accurate potential for level‐resolved vibrationally inelastic scattering.