The most common mechanism of catalytic surface chemistry is that of Langmuir and Hinshelwood (LH). In the LH mechanism, reactants adsorb, become thermalized with the surface, and subsequently react. The measured vibrational (relaxation) lifetimes of molecules adsorbed at metal surfaces are in the range of a few picoseconds. As a consequence, vibrational promotion of LH chemistry is rarely observed, with the exception of LH reactions occurring via a molecular physisorbed intermediate. Here, we directly detect adsorption and subsequent desorption of vibrationally excited CO molecules from a Au(111) surface. Our results show that CO (v = 1) survives on a Au(111) surface for ~1 × 10⁻¹⁰ s. Such long vibrational lifetimes for adsorbates on metal surfaces are unexpected and pose an interesting challenge to the current understanding of vibrational energy dissipation on metal surfaces. They also suggest that vibrational promotion of surface chemistry might be more common than is generally believed.

催化表面化学的最常见机理是Langmuir和Hinshelwood（LH）的机理。在LH机理中，反应物吸附，被表面加热并随后发生反应。测得的吸附在金属表面的分子的振动（松弛）寿命在几皮秒的范围内。结果，除了通过分子物理吸附的中间体发生的LH反应外，很少观察到LH化学的振动促进作用。在这里，我们直接检测振动激发的CO分子从Au（111）表面的吸附和随后的解吸。我们的结果表明，CO（v  = 1）在Au（111）表面上的生存时间约为〜1×10 ^-10 s。金属表面上吸附物的如此长的振动寿命是出乎意料的，并且对当前对金属表面上的振动能量耗散的理解提出了有趣的挑战。他们还暗示，表面化学的振动促进作用可能比普遍认为的更为普遍。