RT Journal Article
SR Electronic
T1 Observation of Partial Wave Resonances in Low-Energy O_{2}–H_{2} Inelastic Collisions
JF Science
JO Science
FD American Association for the Advancement of Science
SP 1094
OP 1096
DO 10.1126/science.1241395
VO 341
IS 6150
A1 Chefdeville, Simon
A1 Kalugina, Yulia
A1 van de Meerakker, Sebastiaan Y. T.
A1 Naulin, Christian
A1 Lique, François
A1 Costes, Michel
YR 2013
UL http://science.sciencemag.org/content/341/6150/1094.abstract
AB Our experience of a world apparently governed by classical physics is a consequence of the fact that quantum mechanical effects average out in size regimes much larger than nanometers. Even at the molecular level, the quantized nature of rotational energy distributions is often obscured by averaging effects. Chefdeville et al. (p. 1094; see the Perspective by Casavecchia and Alexander) have observed a striking manifestation of quantized rotation in the scattering trajectories of colliding H2 and O2 molecular beams. The experimentally resolved partial wave resonances show essentially complete agreement with theoretical calculations and deviate starkly from classical collision paradigms. Partial wave resonances predicted to occur in bimolecular collision processes have proven challenging to observe experimentally. Here, we report crossed-beam experiments and quantum-scattering calculations on inelastic collisions between ground-state O2 and H2 molecules that provide state-to-state cross sections for rotational excitation of O2 (rotational state N = 1, j = 0) to O2 (N = 1, j = 1) in the vicinity of the thermodynamic threshold at 3.96 centimeter−1. The close agreement between experimental and theoretical results confirms the classically forbidden character of this collision-induced transition, which occurs exclusively in a purely quantum mechanical regime via shape and Feshbach resonances arising from partial waves with total angular momentum (J) = 2 to 4.