HCl dissociation on noble metals: A model system for electronically nonadiabatic interactions in chemical reactions at metal surfaces
Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
Final Report Abstract
We have shown that vibrational excitation of HCl molecules scattered from Ag(111) and Au(111) results from interactions that are both electronically adiabatic—T-V energy transfer—as well as electronically nonadiabatic—Born-Oppenheimer failure where vibration couples to metal electrons. The HCl/Ag(111) system exhibits a larger influence of electronic nonadiabaticity compared to the HCl/Au(111) system—this is consistent with the idea that electron transfer is involved in the nonadiabatic energy Transfer mechanism: as work function of Ag is lower than that of Au, allowing an easier production of transient HCl− . Unlike the HCl/Au(111) system, vibrationally inelastic 𝑣 = 1 → 2 transitions could not be seen when HCl (𝑣 = 1) collides with a Ag(111) surface. We suggest that scattering events where HCl (𝑣 = 1) are subject to dynamical influences that increase its vibrational energy, leading efficiently to dissociation before the HCl (𝑣 = 2) molecule can escape the surface. These two systems remain key models for study of Born-Oppenheimer failure in surface chemistry. Future studies are planned to examine the thermal rates of HCl recombinative desorption on Ag and Au using velocity resolved kinetics with an eye toward modeling these reaction with transition state theory. Here, it will in principle be possible to evaluate the influence of quantum effects and electronic nonadiabaticity on the reaction rate constants.
Publications
- Closing the Gap Between Experiment and Theory: Dissociative Chemisorption of HCl on Au(111), J. Phys. Chem. C, 124 (29), 15944-15960 (2020)
Nick Gerrits, Jan Geweke, Egidius W.F. Smeets, Johannes Voss, Alec M. Wodtke, and Geert-Jan Kroes
(See online at https://doi.org/10.1021/acs.jpcc.0c03756) - Vibrationally inelastic scattering of HCl from Ag(111), J. Chem. Phys. 153, 164703 (2020)
Jan Geweke and Alec M. Wodtke
(See online at https://doi.org/10.1063/5.0026228)
