Reactions between cold methyl halide molecules and alkali-metal atoms.

摘要

We investigate the potential energy surfaces and activation energies for reactions between methyludhalide molecules CH3X (X = F, Cl, Br, I) and alkali-metal atoms A (A = Li, Na, K, Rb) usingudhigh-level ab initio calculations. We examine the anisotropy of each intermolecular potential energyudsurface (PES) and the mechanism and energetics of the only available exothermic reaction pathway,udCH3X + A→CH3 + AX. The region of the transition state is explored using two-dimensional PESudcuts and estimates of the activation energies are inferred. Nearly all combinations of methyl halideudand alkali-metal atom have positive barrier heights, indicating that reactions at low temperatures willudbe slow.