SIX-DIMENSIONAL DYNAMICS OF DISSOCIATIVE CHEMISORPTION OFH₂ON METAL SURFACES

Abstract

The theory of time-dependent quantum dynamics of dissociative chemisorption of hydrogen on metal surfaces is reviewed, in the framework of electronically adiabatic scattering from static surfaces. Four implementations of the time-dependent wave packet (TDWP) method are discussed. In the direct product pseudo-spectral and the spherical harmonics pseudo-spectral methods, no use is made of the symmetry associated with the surface unit cell. This symmetry is exploited by the symmetry adapted wave packet and the symmetry adapted pseudo-spectral (SAPS) method, which are efficient for scattering at normal incidence. The SAPS method can be employed for potential energy surfaces of general form. Comparison to experiment shows that the TDWP method yields good, but not yet excellent, quantitative accuracy for dissociation of (ν = 0, j = 0) H 2 if the calculations are based on accurately fitted density functional theory calculations that are performed using the generalized gradient approximation. The influence of the molecule's vibration (rotation) is well (reasonably well) described. The theory does not yet yield quantitatively accurate results for rovibrationally inelastic scattering. The theory has helped with the interpretation of existing experimental results, for instance, by solving a parodox regarding the corrugation of Pt(111) as seen by reacting and scattering H 2. The theory has also provided some exciting new predictions, for instance, concerning where on the surface of Cu(100) H2 reacts depending on its vibrational state. Future theoretical studies of H 2 reacting on metal surfaces will likely be aimed at validating GGAs for molecule-surface interactions, and understanding trends in collisions of H 2 with complex metal surfaces.

Toward Detection of Electron-Hole Pair Excitation in H-atom Collisions with Au(111): Adiabatic Molecular Dynamics with a Semi-Empirical Full-Dimensional Potential Energy Surface

“…Indeed, this class selves also useful to analyze the interaction of molecules with metal surfaces, a seminal early example being the PES cut describing the interaction of H 2 with a copper surface presented by Lennard-Jones in his 1932 paper on adsorption and diffusion on solid surfaces [25]. PESs have also been tremendously useful for studying reactions of molecules on metal surfaces [19,[26][27][28][29][30][31][32][33][34][35][36][37]. Many experimental trends can be understood, and in some cases quantitative agreement with experiment may be obtained, even if electron-hole pair excitation or energy transfer to surface phonons is neglected in these studies.…”

Six-dimensional quasiclassical and quantum dynamics of H2 dissociation on the c(2 × 2)-Ti/Al(100) surface

“…Theoretical progress in gas-surface reaction dynamics 11,[25][26][27][28][29][30][31] Based on a slab model of one ML Ti covered Ti/Al(100) surface, 2 a 6D PES has been built by the density functional theory (DFT) (Refs. 43 and 44).…”

Dynamical pruning of static localized basis sets in time-dependent quantum dynamics

“…A multidimensional wave packet is typically represented by a direct product of reduced-dimensional basis functions or grids; the size of such representations grows exponentially with dimension, limiting TDWP methods to around six degrees of freedom ͑DOFs͒ on currently available computer hardware. 1 ͑Calculations for higher dimensions have been performed in certain favorable cases, 2 but are not generally tractable.͒ Increasing computational resources only allow this effective ceiling on dimensionality to rise slowly over time, so algorithmic improvements are all the more important.…”