One route to break down halomethanes is through reactions with radical species. The capability of the artificial force-induced reaction algorithm to efficiently explore a large number of radical reaction pathways has been illustrated for reactions between haloalkanes (CX3Y; X=H, F; Y=Cl, Br) and ground-state (2Σ+) cyano radicals (CN). For CH3Cl+CN, 71 stationary points in eight different pathways have been located and, in agreement with experiment, the highest rate constant (108 s−1 M−1 at 298 K) is obtained for hydrogen abstraction. For CH3Br, the rate constants for hydrogen and halogen abstraction are similar (109 s−1 M−1), whereas replacing hydrogen with fluorine eliminates the hydrogen-abstraction route and decreases the rate constants for halogen abstraction by 2–3 orders of magnitude. The detailed mapping of stationary points allows accurate calculations of product distributions, and the encouraging rate constants should motivate future studies with other radicals.
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机译：分解卤代甲烷的一种途径是与自由基发生反应。对于卤代烷烃（CX3Y; X = H，F; Y = Cl，Br）与基态（2Σ+）之间的反应，人工力诱导反应算法有效探索大量自由基反应途径的能力已得到说明。氰基（CN）。对于CH3Cl + CN，已经找到了八个不同路径中的71个固定点，并且与实验一致，获得了最高速率常数（在298 K下为108 s-1 M-1）。对于CH3Br，氢和卤素抽象的速率常数相似（109 s-1 M-1），而用氟代替氢消除了氢的吸收途径，并使卤素抽象的速率常数降低了2-3个数量级。固定点的详细映射允许对产品分布进行准确的计算，并且令人鼓舞的速率常数应会激发其他自由基的未来研究。
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