Dissipative dynamics within the electronic friction approach: the femtosecond laser desorption of H2/D2 from Ru(0001)

Abstract

An electronic friction approach based on Langevin dynamics is used to describe the multidimensional (six-dimensional) dynamics of femtosecond laser induced desorption of H(2) and D(2) from a H(D)-covered Ru(0001) surface. The paper extends previous reduced-dimensional models, using a similar approach. In the present treatment forces and frictional coefficients are calculated from periodic density functional theory (DFT) and essentially parameter-free, while the action of femtosecond laser pulses on the metal surface is treated by using the two-temperature model. Our calculations shed light on the performance and validity of various adiabatic, non-adiabatic, and Arrhenius/Kramers type kinetic models to describe hot-electron mediated photoreactions at metal surfaces. The multidimensional frictional dynamics are able to reproduce and explain known experimental facts, such as strong isotope effects, scaling of properties with laser fluence, and non-equipartitioning of vibrational, rotational, and translational energies of desorbing species. Further, detailed predictions regarding translations are made, and the question for the controllability of photoreactions at surfaces with the help of vibrational preexcitation is addressed.

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

“…The model we use to calculate the friction coefficients has been found to be an efficient and sufficiently accurate tool to describe multidimensional adsorbate dynamics driven by hot electrons in an application to femtosecond-laser induced associative desorption of dihydrogen from Ru(0001). 64 As a result of our simulations, we analyze the final state of the scattered molecules. This allows us to compute the state-to-state scattering probabilities P (v i , J i → v f , J f ) from the initial state (v i , J i ) to the final state (v f , J f ).…”

Scattering of Nitrogen Atoms off Ag(111) Surfaces: A Theoretical Study

“…There are recent examples in the literature where the interplay of multidimensional and non-adiabatic effects has been assessed using these methodologies. [6][7][8][9][10][11][12] In the present paper, we have used these techniques to obtain an accurate theoretical description of the N-Ag(111) interaction by means of a full three-dimensional adiabatic PES, constructed from ab-initio data and an elaborate interpolation method. 13 The two types of aforementioned energy loss channels are accounted for later, within classical MD simulations.…”

Communication: Hot-atom abstraction dynamics of hydrogen from tungsten surfaces: The role of surface structure

“…This approximation has been recently used to rationalize the adsorption and relaxation of H, N, and N 2 on bare metallic surfaces, 46,48,50 as well as for recombinative H 2 desorption induced by fs-laser pulses. 65,66 Dissipation to surface phonons is neglected here as dissipation to electrons has been recently predicted to largely dominate the relaxation of hydrogen on metals in the sub-picosecond time scale. [45][46][47][48] As a result of H-atom scattering, recombination may occur via three different processes: ER abstraction is assumed when the formed molecule moves definitively toward the vacuum after the first rebound of the projectile.…”