Excess electron relaxation dynamics at water/air interfaces

Ádám Madarász, Peter J. Rossky, L. Túri

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

We have performed mixed quantum-classical molecular dynamics simulations of the relaxation of a ground state excess electron at interfaces of different phases of water with air. The investigated systems included ambient water/air, supercooled water/air, Ih ice/air, and amorphous solid water/air interfaces. The present work explores the possible connections of the examined interfacial systems to finite size cluster anions and the three-dimensional infinite, fully hydrated electron. Localization site analyses indicate that in the absence of nuclear relaxation the electron localizes in a shallow potential trap on the interface in all examined systems in a diffuse, surface-bound (SB) state. With relaxation, the weakly bound electron undergoes an ultrafast localization and stabilization on the surface with the concomitant collapse of its radius. In the case of the ambient liquid interface the electron slowly (on the 10 ps time scale) diffuses into the bulk to form an interior-bound state. In each other case, the excess electron persists on the interface in SB states. The relaxation dynamics occur through distinct SB structures which are easily distinguishable by their energetics, geometries, and interactions with the surrounding water bath. The systems exhibiting the most stable SB excess electron states (supercooled water/air and Ih ice/air interfaces) are identified by their characteristic hydrogen-bonding motifs which are found to contain double acceptor-type water molecules in the close vicinity of the electron. These surface states correlate reasonably with those extrapolated to infinite size from simulated water cluster anions.

Original languageEnglish
Article number234707
JournalThe Journal of Chemical Physics
Volume126
Issue number23
DOIs
Publication statusPublished - 2007

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Electrons
Water
air
Air
water
electrons
Ice
Anions
ice
anions
nuclear relaxation
Surface states
electron states
Electron energy levels
Ground state
Molecular dynamics
baths
Hydrogen bonds
Stabilization
stabilization

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Excess electron relaxation dynamics at water/air interfaces. / Madarász, Ádám; Rossky, Peter J.; Túri, L.

In: The Journal of Chemical Physics, Vol. 126, No. 23, 234707, 2007.

Research output: Contribution to journalArticle

Madarász, Ádám ; Rossky, Peter J. ; Túri, L. / Excess electron relaxation dynamics at water/air interfaces. In: The Journal of Chemical Physics. 2007 ; Vol. 126, No. 23.
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