The dissociation of water dimers at the MgO(100) surface and MgO ultrathin films on Ag(100) has been studied by means of pure DFT and hybrid functional calculations. We demonstrate that at the intermediate regime between the isolated molecule and the water monolayer, barrierless dissociation of water occurs when assisted by another water molecule. The metal support has been shown to crucially influence the overall process. Indeed, on the metal-supported ultrathin film, the dissociated form is noticeably stabilized, at variance with the MgO(100) surface, where the dissociated fragments can easily recombine. The stabilization of the dissociated charged fragments arises from the polarization of the electron density at the oxide-metal interface and from the polaronic distortion of the oxide film. The presence of the metallic substrate strongly weakens the interaction after the dissociation by changing the nature of the newly formed ion pair, with possible effects on the dynamics and the reactivity of water fragments on the oxide ultrathin film.

Giordano, L., Ferrari, A. (2012). Modified Ion Pair Interaction for Water Dimers on Supported MgO Ultrathin Films. JOURNAL OF PHYSICAL CHEMISTRY. C, 116(38), 20349-20355 [10.1021/jp3050719].

Modified Ion Pair Interaction for Water Dimers on Supported MgO Ultrathin Films

GIORDANO, LIVIA;
2012

Abstract

The dissociation of water dimers at the MgO(100) surface and MgO ultrathin films on Ag(100) has been studied by means of pure DFT and hybrid functional calculations. We demonstrate that at the intermediate regime between the isolated molecule and the water monolayer, barrierless dissociation of water occurs when assisted by another water molecule. The metal support has been shown to crucially influence the overall process. Indeed, on the metal-supported ultrathin film, the dissociated form is noticeably stabilized, at variance with the MgO(100) surface, where the dissociated fragments can easily recombine. The stabilization of the dissociated charged fragments arises from the polarization of the electron density at the oxide-metal interface and from the polaronic distortion of the oxide film. The presence of the metallic substrate strongly weakens the interaction after the dissociation by changing the nature of the newly formed ion pair, with possible effects on the dynamics and the reactivity of water fragments on the oxide ultrathin film.
Articolo in rivista - Articolo scientifico
Oxides, water
English
2012
116
38
20349
20355
none
Giordano, L., Ferrari, A. (2012). Modified Ion Pair Interaction for Water Dimers on Supported MgO Ultrathin Films. JOURNAL OF PHYSICAL CHEMISTRY. C, 116(38), 20349-20355 [10.1021/jp3050719].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/43495
Citazioni
  • Scopus 18
  • ???jsp.display-item.citation.isi??? 19
Social impact