Quantum trajectory capture for complex-forming reactions

International audienceWhile direct reactions with activation barriers are now routinely calculated, reactions going through a longlivedintermediate complex are much more difficult to study[1, 2]. Complex-forming reactions are often barrierlessand are thus relevant to the field of cold and utra-cold chemistry [2]. With decreasing temperature, wave effectsbecome increasingly important and may dominate the collisional behavior at ultralow temperatures.Capture theories (close-coupling expansion with boundary conditions applied in the reactant channel) are oftenused to study complex-forming reactions [3, 4]. In this contribution we propose a new approach that describes thecapture process by evolving quantum trajectories in the reactant channel up to a given limit inside the centrifugalbarrier. The quantum trajectories take full account of quantum effects [5] along the reaction path direction. Inparticular, tunneling effects, which can change the reaction rate by orders of magnitude, are accurately computed.Apart from the entrance channel motion, which is guided by quantum trajectories, all other coordinates aretreated classically [6]. Our trajectory method is thus highly "classical-like" [6]. It is aimed at large system reactionswith quantum effects, still out of reach for current quantum scattering codes. Preliminary results will be presentedat the conference.References[1] H. Guo, Rev. Phys. Chem. 31, 1 (2012).[2] M. T. Bell, and T. P. Softley, Mol. Phys. 99, 107 (2009).[3] D.C. Clary and J.P. Henshaw, Faraday Discuss. Chem. Soc. 84, 333 (1987).[4] E.J. Rackham, T. Gonzalez-Lezana, and D.E. Manolopoulos, J. Chem. Phys. 119, 12895 (2003).[5] B. Poirier, Chem. Phys. 370, 4 (2010).[6] G. Parlant, Y.-C. Ou, K. Park, and B. Poirier, Comp. Theor. Chem. 990, 3 (2012)