Plasmon excitation has been widely used in surface-enhanced Raman spectroscopy (SERS). Generation of highly energetic carriers or so-called “hot” carriers (electrons and holes) in plasmonic nanostructures, through electromagnetic decay of a collective oscillation of the conduction electrons in resonance with the frequency of incident light, known as a localized surface plasmon resonance (LSPR), has shown valuable applications in solar cells, sensors, photodetectors, and catalysis. In this work, NH3 molecule desorption and dissociation processes are studied on Ru doped Cu(111) surface. Early experimental works of Inelastic Electron Tunneling Spectroscopy (IETS) where, by tuning tunneling voltage in STM, one can couple the tunneling current with distinct molecular motions. In the case of NH3 on Ru@Cu(111), it was demonstrated that two motions, desorption and diffusion, could be selectively triggered by the tunneling electrons of different energy. The question is if we can achieve similar selectivity by using different photons. Our real time TDDFT (rt-TDDFT) based Ehrenfest molecular dynamics simulations suggest that such fine control is possible. Our results show that two motions (decomposition vs desorption) of NH3 can be triggered on Ru@Cu(111) under two laser pulses with different energies at 1.26 and 2.12 eV. Furthermore, it may be possible to incorporate other transition metals (e.g., Mn, Fe, Co, Ni) with the aim of reducing the required light intensity. This study not only explores the feasibility of tuning reaction pathways using light but also offers insights into catalyst design strategies to enable such tunability.
