Analysis of lateral hopping of a single CO molecule on Pd(110)

Lateral hopping of a single CO molecule on Pd(110) by Komeda et al. [Science 295, 2055 (2002)] is revisited using a recently proposed formula of reaction yield $Y(V)$ as a function of bias voltage V. The calculated $Y(V)$ using a Lorentzian vibrational density of states (DOS) for the C-O stretch mode meets with a better agreement with the experimental data than using a Gaussian DOS. It is also found that the broadening used in the fitting to the experimental result is very close to the intrinsic vibrational lifetime of the C-O stretch mode on Pd (110). Using the fitting parameters of the transition rate to excite the frustrated translation mode above the barrier, the anharmonic coupling of the C-O stretch mode to the frustrated translation mode is determined for the first time from the analysis of the experimental result.