Role of electronic friction during the scattering of vibrationally excited nitric oxide molecules from Au(111)

Abstract

Some time ago, it has been observed that vibrationally highly excited NO͑v͒ molecules ͑with typical vibrational quantum numbers v Ϸ 15͒ lose substantial amounts of vibrational energy when scattering off a Au͑111͒ surface ͓H. Huang, C. Rettner, D. Auerbach, and A. Wodtke, Science 290, 111 ͑2000͔͒. This has been interpreted as a sign for the breakdown of the Born-Oppenheimer approximation due to vibration-electron coupling. It has been argued that this process cannot be understood on the basis of single-quantum transitions which are typical for "electronic friction" models based on a perturbative treatment of weak vibration-electron couplings. Rather, multiple-quanta transitions characteristic for strong nonadiabatic effects are needed according to recent classical surface hopping calculations involving multiple potential-energy surfaces and model Hamiltonians ͓N. Shenvi, S. Roy, and J. C. Tully, Science 326, 829 ͑2009͔͒. Here we address the importance and magnitude of electronic friction for NO@ Au͑111͒ by using fully quantum-mechanical, parameter-free first-principles theories in reduced dimensions. Periodic density-functional theory calculations are performed to obtain a ground-state potential-energy surface along the desorption and NO-vibration coordinates, and coordinate-resolved, finite NO vibrational lifetimes due to vibration-electron coupling. Using this input, the scattering event is modeled by open-system density-matrix theory in the frame of the coupled-channel-densitymatrix method, which allows for the inclusion of energy relaxation of the scattering NO molecules. It is found that within this model at least, electronic friction accounts for the observed vibrational deactivation of NO scattering from gold.

Vibrationally promoted electron emission at a metal surface: electron kinetic energy distributions

“…For example, multi-quantum vibrational relaxation of NO(v = 14,15) on Au(111) is at least semi-quantitatively reproduced by friction-like theories. 13 However, good agreement with experiment is also found using a multi-state (independent electron surface hopping) model, [14][15][16] where a single electron transfer mechanism is operative.…”

“…For example, multi-quantum vibrational relaxation of NO(v = 14,15) on Au(111) is at least semi-quantitatively reproduced by friction-like theories. 13 However, good agreement with experiment is also found using a multi-state (independent electron surface hopping) model, 14-16 where a single electron transfer mechanism is operative.Putting it another way, a fundamental unknown is the fraction of molecular vibration that can be converted to single electron excitation and vice versa. For example, one might envision that a single highly excited electron in a solid could transfer nearly all of its excitation energy to a molecule at the surface.…”

Vibrational deexcitation and rotational excitation of H2 and D2 scattered from Cu(111): Adiabatic versus non-adiabatic dynamics

“…Thus, Shenvi et al 12,13 have been able to explain the observed multi-quantum vibrational relaxation of NO scattered from Au(111) using a model that incorporates electron hopping between the surface and the molecule. More recently, low dimensional calculations performed by Monturet et al 14 suggest that an electronic friction model may also account for many of the results obtained in this kind of experiment.…”

The importance of accurate adiabatic interaction potentials for the correct description of electronically nonadiabatic vibrational energy transfer: A combined experimental and theoretical study of NO(v = 3) collisions with a Au(111) surface

“…Experimental results showed that NO in high vibrational states (v i = 15), incident with translational energy of 0.05 eV, relax into a broad range of vibrational states when scattered from a gold surface. 16 Several different theoretical approaches semi-quantitatively reproduce the observed vibrational state distributions, including a Monte Carlo model with stochastic quantum jumps between the neutral and negative ion states of the molecule, 17 fully quantum mechanical first-principles EF theory, 18 and molecular dynamics (MD) employing Independent Electron Surface Hopping (IESH) on a density functional theory (DFT) based Newns-Anderson Hamiltonian. [19][20][21][22] In order to attempt to distinguish between these various theoretical approaches, a comprehensive series of experiments was performed to study the collision-induced vibrational excitation of NO(v = 0) into vibrational states v = 1, 2 when scattered from a Au(111) surface over a wide range of incidence energies and surface temperatures (300 K ≤ T s ≤ 1000 K and 0.11 eV ≤ E i ≤ 1.05 eV).…”