Molecule-surface collisions are analyzed classically using a two-dimensional hard-core ellipsoidflat-surface model. Closed expressions are derived for the maximal excitations and deexcitations of the rotational transitions for an initially rotating molecule in the state j0. These bounds are not symmetric with respect to j0. We make comparisons with the predictions of the infiniteorder sudden approximation, and show that it is not suitable for analyzing quantitatively the problem of transition bounds. A classical condition for the onset of multiple molecule-surface collisions is also derived, which is applicable to both the initially rotating and nonrotating molecules. Quantum two-dimensional calculations fully support the results of the classical analysis.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics