The detailed potential energy surface for the key atmospheric reaction of OH with CH 2 @CHCH(OH)CH 3 (3-buten-2-ol) has been investigated at the CCSD(T)/6-311++G(d,p)//MP2(full)/6-311++G(d,p) level. Various possible H-abstraction and addition-elimination pathways are identified. It is predicted that the formation of intermediates c1 ( Γ
CH 2 CH(OH)CH(OH)CH 3 ) in the addition process via pre-reactive complex a3 is more favorable than that of the H-abstraction reactions at low temperature. Starting from c1, the most feasible pathway is the formation of P7 (CH 2 @CHOH(I)
CH 3 Γ
CHOH(I)) by directly CAC bond rupture or formation of P14 (CH 3 CHO + CH 3 Γ
CHOH(I)) via isomerization/dissociation mechanisms, all of which have comparable contributions to the title reaction. P14 (CH 3 CHO + CH 3 Γ
CHOH(I)) are the dominate products.
In the H-abstraction pathways, the dominant channel is the allylic H atom abstraction leading to P5 (CH 2 @CH Γ
C(OH)CH 3 ) + H 2 O, which may play an important role at higher temperature. The other pathways are less significant due to higher barrier height and unstable product. This calculation is useful to simulate to guide experimental investigations of the title reaction.