Electrons in finite-sized water cavities: Hydration dynamics observed in real time

D. Hern Paik, I. Ren Lee, Ding Shyue Yang, J. Spencer Baskin, Ahmed H. Zewail*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

208 Citations (Scopus)


We directly observed the hydration dynamics of an excess electron in the finite-sized water clusters of (H2O)n- with n = 15, 20, 25, 30, and 35. We initiated the solvent motion by exciting the hydrated electron in the cluster. By resolving the binding energy of the excess electron in real time with femtosecond resolution, we captured the ultrafast dynamics of the electron in the presolvated ("wet") and hydrated states and obtained, as a function of cluster size, the subsequent relaxation times. The solvation time (300 femtoseconds) after the internal conversion [140 femtoseconds for (H2O)35-] was similar to that of bulk water, indicating the dominant role of the local water structure in the dynamics of hydration. In contrast, the relaxation in other nuclear coordinates was on a much longer time scale (2 to 10 picoseconds) and depended critically on cluster size.

Original languageEnglish
Pages (from-to)672-675
Number of pages4
Issue number5696
Publication statusPublished - 2004 Oct 22
Externally publishedYes

ASJC Scopus subject areas

  • General


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