Chemical dynamics from the gas‐phase to surfaces

Abstract

The field of gas‐phase chemical dynamics has developed superb experimental methods to probe the detailed outcome of gas‐phase chemical reactions. These experiments inspired and benchmarked first principles dynamics simulations giving access to an atomic scale picture of the motions that underlie these reactions. This fruitful interplay of experiment and theory is the essence of a dynamical approach perfected on gas‐phase reactions, the culmination of which is a standard model of chemical reactivity involving classical trajectories or quantum wave packets moving on a Born–Oppenheimer potential energy surface. Extending the dynamical approach to chemical reactions at surfaces presents challenges of complexity not found in gas‐phase study as reactive processes often involve multiple steps, such as inelastic molecule‐surface scattering and dissipation, leading to adsorption and subsequent thermal desorption and or bond breaking and making. This paper reviews progress toward understanding the elementary processes involved in surface chemistry using the dynamical approach. Key points The fruitful interplay between chemistry and physics leads to an atomic scale view of reactions taking places at catalytically active surfaces. Improved observations of chemical reactions taking place in complex environments drive the development of new approaches to theoretical chemistry. Complex reaction networks from real catalysts are boiled down to their elementary steps and examined from first principles.

Prominence of Terahertz Acoustic Surface Plasmon Excitation in Gas–Surface Interaction with Metals

“…The classical understanding of gas–surface dynamics based on direct collisions with the surface atoms is that the excess kinetic energy of the colliding particles is transferred to the vibrational degrees of freedom of the target. − This process was demonstrated to dominate, e.g., for dissociation of H 2 on Cu(111) and Ru(0001), methane on Ni(100), and water on Ni(111) . Energy transfer to the electronic degrees of freedom (electron–hole (e–h) pair excitations) was observed only for much higher energies: impact energies of several electronvolts for H and HCl scattering off Au(111) and high vibrational excitation for NO dissociation on Au(111). , In all of these cases, as well as in the interpretation of friction phenomena, only e–h pair generation was considered.…”

Dissipative tunneling rates through the incorporation of first-principles electronic friction in instanton rate theory. I. Theory

“…Thus, low energy excitation and deexcitation of electron-hole pairs can easily exchange energy with nuclear vibrations, representing a violation of the Born-Oppenheimer principle, where electrons are assumed to adjust adiabatically to the position of the nuclei. This type of non-adiabatic effect (NAE) has been verified experimentally numerous times in the past [1][2][3] and found to be particularly important for hot-electron-induced reactions, 4 surface scattering, 5,6 and vibrational relaxation lifetimes. [7][8][9] Many theoretical approaches have been developed to account for NAEs in these contexts.…”

Dissipative Tunneling Rates through the Incorporation of First-Principles Electronic Friction in Instanton Rate Theory I: Theory

“…Thus, low energy excitation and deexcitation of electron-hole pairs can easily exchange energy with nuclear vibrations, representing a violation of the Born-Oppenheimer principle, where electrons are assumed to adjust adiabatically to the position of the nuclei. This type of non-adiabatic effect (NAE) has been verified experimentally numerous times in the past [1][2][3] and found to be particularly important for hot-electron-induced reactions 4 , surface scattering 5,6 and vibrational relaxation lifetimes [7][8][9] . Many theoretical approaches have been developed to account for NAEs in these contexts [10][11][12][13] .…”