Maurer Reinhard J, Jiang Bin, Guo Hua, Tully John C
Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
Department of Chemical Physics, University of Science & Technology of China, Hefei, Anhui 230026, China.
Phys Rev Lett. 2017 Jun 23;118(25):256001. doi: 10.1103/PhysRevLett.118.256001.
Electronic friction and the ensuing nonadiabatic energy loss play an important role in chemical reaction dynamics at metal surfaces. Using molecular dynamics with electronic friction evaluated on the fly from density functional theory, we find strong mode dependence and a dominance of nonadiabatic energy loss along the bond stretch coordinate for scattering and dissociative chemisorption of H_{2} on the Ag(111) surface. Exemplary trajectories with varying initial conditions indicate that this mode specificity translates into modulated energy loss during a dissociative chemisorption event. Despite minor nonadiabatic energy loss of about 5%, the directionality of friction forces induces dynamical steering that affects individual reaction outcomes, specifically for low-incidence energies and vibrationally excited molecules. Mode-specific friction induces enhanced loss of rovibrational rather than translational energy and will be most visible in its effect on final energy distributions in molecular scattering experiments.
电子摩擦及随之产生的非绝热能量损失在金属表面的化学反应动力学中起着重要作用。利用基于密度泛函理论即时评估电子摩擦的分子动力学方法，我们发现H₂在Ag(111)表面散射和解离化学吸附时，非绝热能量损失强烈依赖于模式，且沿键伸缩坐标占主导地位。具有不同初始条件的典型轨迹表明，这种模式特异性在解离化学吸附过程中转化为调制能量损失。尽管非绝热能量损失较小，约为5%，但摩擦力的方向性会引发动力学操控，影响单个反应结果，特别是对于低入射能量和振动激发分子。模式特异性摩擦导致振转能量而非平动能量的损失增加，这在分子散射实验中对最终能量分布的影响最为明显。
