Dissociative dynamics of O₂ on Ag(110)

Abstract

We study the dissociative dynamics of O2 on Ag(110) by performing classical and quasiclassical trajectory calculations on an adiabatic six-dimensional potential energy surface (PES). The PES is constructed from the interpolation of a large set of energies that are calculated using spin-polarized density functional theory. The minimum energy barrier to dissociation amounts to 0.36 eV. This value, which is considerably lower than the barriers of about 1.1 eV found in the Ag(100) and Ag(111) surfaces, is in line with the measured much higher reactivity of the (110) surface. Our classical dynamics calculations show that under normal incidence conditions no significant dissociation occurs below an initial energy of 0.9 eV (0.6 eV in the quasiclassical calculations). This result is an indication of a very much reduced configurational space leading to dissociation and also explains why direct dissociation has not been observed experimentally at low incidence energies. Our calculations also show that for off-normal incidence, most of the dissociation takes place close to the long-bridge site, a region of the configurational space where the energy barriers to dissociation are higher than 0.7 eV, resulting in still lower dissociation probabilities.

Femtosecond-laser-driven molecular dynamics on surfaces: Photodesorption of molecular oxygen from Ag(110)

“…Additional details are given in Ref. [25]. The oxygen molecule on Ag(110), as predicted by DFT with the PBE exchange-correlation functional, features the four adsorption wells sketched in Fig.…”

“…The ground state properties of O 2 on Ag(110) are described by a recently constructed 6D PES [25] that is obtained from the CRP interpolation of ∼ 25000 spinpolarised DFT energies. The latter were calculated with the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional [53] as implemented in the VASP code [54,55] and with a plane-wave basis set energy cut-off of 400 eV.…”

“…In these conditions it is not possible to perform a more detailed analysis of the process. Still, the occurrence of dissociation events is an interesting result considering that the energy barrier to dissociation is 0.57 eV [25], significantly larger than the well depth of −0.21 eV.…”

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

“…Large effects are also experimentally and theoretically observed in the initial sticking probability of N 2 on tungsten surfaces [7][8][9][10] and O 2 on the three low-index crystal faces of silver. [11][12][13][14][15][16][17] Molecular recombination is also affected by the crystal face as revealed, for instance, by the experiments on hydrogen formation at metals carried out by Küppers et al [18][19][20][21][22][23][24][25] and Winkler et al [26][27][28][29] The observed kinetics for H(D)+D(H)/metal recombination has been rationalized via models that required a significant variation of the rate constants for H 2 , HD, and D 2 formations for the three low-index faces of Pt [19][20][21][22] and also for Cu(111) and Cu(100). 23,24 On the sub-picosecond time scale, recombinations proceed via Eley-Rideal (ER) or Hot-Atom (HA) abstractions.…”

Adatom Extraction from Pristine Metal Terraces by Dissociative Oxygen Adsorption: Combined STM and Density Functional Theory Investigation of O/Ag(110)

“…With the latter technology, already applied in Refs. [23,28,35], the O 2 sticking probability is increased due to the hyperthermal energy, so that clean experiments at coverages precluded in backfilling conditions are possible [35,36]. Details about the experimental protocol and the DFT calculations for the energetics and simulation of STM images can be found in the Supporting Online Material (SOM).…”