Despite significant progress made in past decades, it is still challenging to elucidate dynamics mechanisms for polyatomic reactions, in particular, involving complex formation. The reaction of O(D-1) with methane has long been regarded as a prototypical polyatomic system of direct insertion reaction in which the O(D-1) atom can insert into the C-H bond of methane to form a "hot" methanol intermediate before decomposition. Here, we report a combined theoretical and experimental study on the O(D-1) + CHD3 reaction, on which good agreement between theory and experiment is achieved. Our study revealed that this complex-forming reaction actually proceeds via a trapped abstraction mechanism, rather than an insertion mechanism as has long been thought. We anticipate that this reaction mechanism should also be responsible for the reaction of O(D-1) with ethane and propane, as well as many other chemical reactions with deep wells in the interaction region.
