Ultrafast Dynamics of Electron Localization and Solvation in Ice Layers on Cu(111)

Abstract

The femtosecond dynamics of localization and solvation of photoinjected electrons in ultrathin layers of amorphous solid H2O and D2O have been studied by time- and angle-resolved two-photon-photoelectron spectroscopy. After electron transfer from the metal substrate into the conduction band of ice, the excess electron localizes within the first 100 fs in a state at 2.9 eV above E(F), which is further stabilized by 300 meV on a time scale of 0.5-1 ps due to molecular rearrangements in the adlayer. A pronounced change of the solvation dynamics at a coverage of approximately 2 bilayers is attributed to different rigidity of the solvation shell in the bulk and near the surface of ice.

Direct Observation of Two-Dimensional Electron Solvation at Alcohol/Ag(111) Interfaces

“…3,43,44 The effects of deuteration depend critically on the solvent modes responsible for solvation and may be influenced by the nature of the probe solute. 43,44 Isotope effects should be most apparent in the high-frequency librational modes of the solvent, as demonstrated by experiments on excess electrons in liquid water that probed the solvent response at sub-50 fs time scales.…”

“…The dynamics of these processes can be complicated by the presence of an electron at the surface. A strong electron-adsorbate interaction can cause an electron induced adsorbate reorganization [1][2][3] similar to electron solvation in liquids. [4][5][6] In liquids, electron solvation dynamics are known to critically influence the rates of a wide variety of processes, including vibrational relaxation, [7][8][9] ion transport, 10 molecular isomerization, 8,11 protein folding, 12 and electron-transfer reactions.…”

Decay of electronic excitations at metal surfaces

“…Of particular interest has been the decoupling of the states from the metallic substrate by insulating spacers. The possibility to increase the lifetime in this way has been crucial for recent 2PPE experiments on the dynamics of localization due to small polaron formation [250,251] and electron solvation [252][253][254]. Likewise, in conventional photoemission work, rare-gas layers have been employed successfully to resolve the vibrational fine structure of 2D molecular layers [255][256][257].…”

The Ultrafast Dynamics of Image Potential State Electrons at the Dimethylsulfoxide/Ag(111) Interface

“…26 Electrons at interfaces have shown dynamic m* shifts and/or localization over time. 23,27 The kinetic energy of an electron photoemitted from a localized state is invariant to collection angle and does not display the k ║ -dependence of a delocalized state described by Equation 4. The localized state can be described by a weighted sum of plane waves,…”