Breakdown of the Born-Oppenheimer approximation in the F+ o-D2 -> DF + D reaction.
The reaction of F with H2 and its isotopomers is the paradigm for an exothermic triatomic abstraction reaction. In a crossed-beam scattering experiment, we determined relative integral and differential cross sections for reaction of the ground F(2P(3/2)) and excited F*(2P(1/2)) spin-orbit states with D2 for collision energies of 0.25 to 1.2 kilocalorie/mole. At the lowest collision energy, F* is approximately 1.6 times more reactive than F, although reaction of F* is forbidden within the Born-Oppenheimer (BO) approximation. As the collision energy increases, the BO-allowed reaction rapidly dominates. We found excellent agreement between multistate, quantum reactive scattering calculations and both the measured energy dependence of the F*/F reactivity ratio and the differential cross sections. This agreement confirms the fundamental understanding of the factors controlling electronic nonadiabaticity in abstraction reactions.
Che
Li
L
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, People's Republic of (P. R.) China.
Ren
Zefeng
Z
Wang
Xingan
X
Dong
Wenrui
W
Dai
Dongxu
D
Wang
Xiuyan
X
Zhang
Dong H
DH
Yang
Xueming
X
Sheng
Liusi
L
Li
Guoliang
G
Werner
Hans-Joachim
HJ
Lique
François
F
Alexander
Millard H
MH