Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 17 June 2005:
Vol. 308. no. 5729, pp. 1765 - 1769
DOI: 10.1126/science.1113094
Prev | Table of Contents | Next

Reports

Spectral Signatures of Hydrated Proton Vibrations in Water Clusters

Jeffrey M. Headrick,1 Eric G. Diken,1 Richard S. Walters,2 Nathan I. Hammer,1 Richard A. Christie,3 Jun Cui,3 Evgeniy M. Myshakin,3 Michael A. Duncan,2* Mark A. Johnson,1* Kenneth D. Jordan3*

The ease with which the pH of water is measured obscures the fact that there is presently no clear molecular description for the hydrated proton. The mid-infrared spectrum of bulk aqueous acid, for example, is too diffuse to establish the roles of the putative Eigen (H3O+) and Zundel (H5O2+) ion cores. To expose the local environment of the excess charge, we report how the vibrational spectrum of protonated water clusters evolves in the size range from 2 to 11 water molecules. Signature bands indicating embedded Eigen or Zundel limiting forms are observed in all of the spectra with the exception of the three- and five-membered clusters. These unique species display bands appearing at intermediate energies, reflecting asymmetric solvation of the core ion. Taken together, the data reveal the pronounced spectral impact of subtle changes in the hydration environment.

1 Sterling Chemistry Laboratory, Yale University, Post Office Box 208107, New Haven, CT 06520, USA.
2 Department of Chemistry, University of Georgia, Athens, GA 30602, USA.
3 Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.

* To whom correspondence should be addressed. E-mail: maduncan{at}uga.edu (M.A.D.), mark.johnson{at}yale.edu (M.A.J.), jordan{at}pitt.edu (K.D.J.)

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Real-time molecular monitoring of chemical environment in obligate anaerobes during oxygen adaptive response.
H.-Y. N. Holman, E. Wozei, Z. Lin, L. R. Comolli, D. A. Ball, S. Borglin, M. W. Fields, T. C. Hazen, and K. H. Downing (2009)
PNAS 106, 12599-12604
   Abstract »    Full Text »    PDF »
Aggregation-Induced Dissociation of HCl(H2O)4 Below 1 K: The Smallest Droplet of Acid.
A. Gutberlet, G. Schwaab, O. Birer, M. Masia, A. Kaczmarek, H. Forbert, M. Havenith, and D. Marx (2009)
Science 324, 1545-1548
   Abstract »    Full Text »    PDF »
Amino acids with an intermolecular proton bond as proton storage site in bacteriorhodopsin.
P. Phatak, N. Ghosh, H. Yu, Q. Cui, and M. Elstner (2008)
PNAS 105, 19672-19677
   Abstract »    Full Text »    PDF »
Structures and spectral signatures of protonated water networks in bacteriorhodopsin.
G. Mathias and D. Marx (2007)
PNAS 104, 6980-6985
   Abstract »    Full Text »    PDF »
Sequential Proton Transfer Through Water Bridges in Acid-Base Reactions.
O. F. Mohammed, D. Pines, J. Dreyer, E. Pines, and E. T. J. Nibbering (2005)
Science 310, 83-86
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)