AN ANALYSIS OF ROTATIONAL TRANSITION-PROBABILITIES AND CROSS-SECTIONSUSING CLOSE-COUPLING, HARD SHAPE, AND CLASSICAL TRAJECTORY METHODS

Classical and quantum transition probabilities were calculated applyin g the two (2D) and three (3D) dimensional close-coupled and classical trajectory methods. The collision energy was 0.01 eV and, in this case , there are 12 classical accessible states for Xe-CO2 collisions. It w as shown that for Delta j greater than or equal to 8 the 2D and 3D tra nsition probabilities agree quantitatively. The state-to-state total c ross sections were also compared, in the same level of dimension, and the results showed similar trends. In addition, the hard shape quantum cross sections were compared with the 2D results and showed that the classical turning point cannot be used to obtain the semi-axes of the ellipse, namely A and B. Moreover, the intensity of the hard shape cro ss sections showed to be different either for the 2D or 3D close coupl ing calculations. The comparison between the transition probabilities, carried out by the 2D and 3D quantum methods, showed the nature of th e 2D results with accurate agreement for large Delta j transitions. (C ) 1996 American Institute of Physics.