Dynamics of the S(D21)+HD(j=0) reaction at collision energies approaching the cold regime: A stringent test for theory

We report integral cross sections for the S(1D2) + HD(j = 0) → DS + H and HS + D reaction channels obtained through crossed-beam experiments reaching collision energies as low as 0.46 meV and from adiabatic time-independent quantum-mechanical calculations. While good overall agreement with experiment at energies above 10 meV is observed, neither the product channel branching ratio nor the low-energy resonancelike features in the HS + D channel can be theoretically reproduced. A nonadiabatic treatment employing highly accurate singlet and triplet potential energy surfaces is clearly needed to resolve the complex nature of the reaction dynamics
The authors gratefully acknowledge the Agence Nationale de la Recherche (Contract No. ANRBLAN- 2006-0247), the Conseil Régional d’Aquitaine (Contract No. 2007.1221) and Comunidad de Madrid (Project No. S2009/MAT/1476) for their support of this work