Suchergebnisse

The stereodynamics of the Ar + NO (J = 0) rotational inelastic excitation has been investigated at 66 meV by means of quasiclassical trajectories on a recent ab initio potential energy surface. A marked correlation between the preferred sense of rotation of NO and the scattering plane is obtained for the highest rotational levels accessible, which are excited in strong repulsive collisions. This result is in qualitative agreement with recent quantum mechanical calculations and experimental measurements. For the lower rotational levels, where the interactions are not so repulsive, the preferred sense of rotation is found to oscillate with scattering angle, but the intensity of the oscillations is small and their angular range is not entirely coincident with those from quantum mechanics and experiment. Classical dynamics, even including attractive interactions, cannot account properly for the mentioned oscillatory behaviour. Secondary encounters between the outgoing Ar atom and NO molecule, giving rise to 'chattering', are found to be relatively frequent, leading to a decrease in the final rotational energy of NO with respect to that attained in the first encounter. Chattering trajectories are defined and their mechanism is characterized. © Royal Society of Chemistry ; Funded by the Ministry of Science and Technology of Spain under grants BQU2002-04627-C02 and REN 2000-1557 and by the European Union through the RTN Reaction Dynamics(HPRN-CT-1999-0007). The research was performed within the Unidad Asociada ''Química Física Molecular'' between the Universidad Complutense and the CSIC. ; Peer Reviewed

The rotationally inelastic scattering of NO by Ar was studied on a potential energy surface at the collision energy of a high resolution experiment. The study entailed the calculationm of the state-resolved integral and differential cross sections for all the excited levels of NO in the lowest spin-orbit manifold. The quasiclassical approach was shown to satisfactorily reproduce few observations seen in both the experimental and quantum mechanical state-resolved differential cross-sections. © 2003 American Institute of Physics ; Funded by the Ministry of Science and Technology of Spain under Grants No. BQU2002-04627-C02 and No. REN 2000-1557, by the European Union through the RTN Reaction Dynamics ~HPRN-CT-1999-0007!, and by the U.S. National Science Foundation ~Grant No. CHE-9971810! The research was performed within the Unidad Asociada ''Química Física Molecular'' between the Universidad Complutense and the CSIC. ; Peer Reviewed