Quasiclassical trajectory calculations of collisional energy transfer in propane systems

Quasiclassical trajectory calculations of collisional energy transfer (CET) and rotational energy transfer from highly vibrationally excited propane to rare bath gases are reported. The calculations employed atom-atom pairwise-additive Lennard-Jones, Buckingham-exponential and hard-sphere intermolecular potentials to examine the dependence of CET on the intermolecular potential and to establish a protocol for future work on larger alkane systems. The role of the torsional (internal) and molecular (external) rotors in the energy-transfer mechanism were investigated. Comparison of the results with our earlier work on ethane+neon systems [Phys. Chem. Chem. Phys. 1999, 1, 3467] suggests that the internal and external rotors play a significant role in the deactivation mechanism for highly vibrationally excited alkanes.