Effect of the Vibrational/Rotational Energy Partitioning on the Energy Transfer in Atom-Triatomic Molecule Collisions

摘要

The effect of the initial partitioning of the molecular energy between vibrational and rotational modes of a triatomic molecule on the collisional energy transfer is studied for a model atom-triatomic molecule system. We considered the collisions of thermal bath Ar atoms with SO2 molecules, and used the trajectory calculations for determining the energy transfer for three different samplings of initial conditions of the molecule. The first sampling method generated the microcanonical distribution over all states, entering into the vibrational and rotational manifolds, while two others produced distributions with relatively lower values of the rotational energies. It is shown that both the average energy transfer per collision and the mechanism of the energy exchange are significantly affected by the vibrational/rotational energy partitioning before the collisions. Relative decrease in the rotational energy results in the decrease of the averaged energy transfer and progressively emphasizes the role of active rotation as the gateway for translation-vibration energy exchange.