Classical dynamics of dissociative adsorption for a nonactivated system: The role of zero point energy

Abstract

We present dissociative adsorption probabilities of H 2 on Pd͑111͒ computed with the classical trajectory method. We perform both classical ͑C͒ and quasiclassical ͑QC͒ calculations, the latter including, by contrast with the former, the initial zero point energy ͑ZPE͒ of H 2 . We analyze in detail the role played by the ZPE and demonstrate the strong and weak points of both C and QC calculations. We show that ZPE is crucial in accelerating the molecules toward the surface through vibrational softening. However, at low energies, dynamic trapping is quenched in QC calculations by processes of vibration to rotation energy transfer that would be associated with closed channels in a quantum approach. In this study we use a new representation of the H 2 /Pd(111) potential energy surface ͑obtained by interpolation of ab initio data͒ with a significantly better accuracy in the entrance channel region which plays a decisive role in the dissociation dynamics.

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

“…37 and 83), H 2 + Pd(111) (Ref. 84), and H 2 + Pd(110) (Ref. 85) systems, in which trapping promotes reaction by providing the system with a longer time to reach an optimal configuration to overcome the barrier.…”

Dynamics of H2 Eley-Rideal abstraction from W(110): Sensitivity to the representation of the molecule-surface potential

“…One of the PESs (hereafter referred to as FPLEPS) is a result of a global analytical fitting 52, 53 using a generalization [54][55][56] of the LondonEyring-Polanyi-Sato (LEPS) function [57][58][59] widely used in the past to investigate H+H ER abstraction processes on metal surfaces. 12,14,20,21,25,43,44,46 The other PES (hereafter referred to as CRP) has been obtained by interpolation using the corrugation reducing procedure 60 which has been widely used 42,49,[60][61][62][63][64][65][66][67][68][69][70][71][72][73][74] and successfully gauged against AIMD results 49,75 of dissociative adsorption probabilities but scarcely used to investigate ER abstraction processes. It has to be mentioned that CRP has already been used in the context of recombination process but for modeling the LangmuirHinshelwood mechanism (LH), 76 which can be seen as the reverse mechanism of dissociative adsorption.…”

Comment on “Reactive force fields for surface chemical reactions: A case study with hydrogen dissociation on Pd surfaces” [J. Chem. Phys. 132, 014704 (2010)]

“…no longer any spurious oscillation. For the rigid substrate, the new SMA RFF leads to a lower minimum for the sticking coefficient, S 0 , than that obtained from the molecular dynamics (MD) simulation by using REBO potential energy surface (PES), i.e., REBO(PES)-MD, 1 and gives results closer to those obtained from MD simulations based on a PES constructed by using the corrugation-reducing procedure, i.e., CRP(PES)-MD, 4 in the low incident energy region but overestimates the sticking coefficient in the high incident energy region. For the nonrigid substrate, the current SMA(PES)-MD simulation gives the minimum value of S 0 much closer to the result found from AIMD (Ref.…”