Intra- and Intermolecular Vibrational De-excitation in Impulsive Atom–Diatomic Molecule Collisions

The de-excitation of vibrationally energetic Morse oscillators via impulsive collision with an atom is discussed. In certain types of atom–oscillator systems intramolecular vibration-to-rotation energy transfer is more important than intermolecular vibration-to-translation transfer. Since the efficiency of this intramolecular de-excitation has a different dependence on particle mass and collision energy than does the intermolecular de-excitation, restricting consideration to the latter, e.g., using a collinear collision model, does not always lead to an adequate description of the de-excitation process.