Abstract
The Grotthuss mechanism explains the anomalously high proton mobility in water as a sequence of proton transfers along a hydrogen-bonded (H-bonded) network. However, the vibrational spectroscopic signatures of this process are masked by the diffuse nature of the key bands in bulk water. Here we report how the much simpler vibrational spectra of cold, composition-selected heavy water clusters, D+(D2O)n, can be exploited to capture clear markers that encode the collective reaction coordinate along the proton-transfer event. By complexing the solvated hydronium "Eigen" cluster [D3O+(D2O)3] with increasingly strong H-bond acceptor molecules (D2, N2, CO, and D2O), we are able to track the frequency of every O-D stretch vibration in the complex as the transferring hydron is incrementally pulled from the central hydronium to a neighboring water molecule.
| Original language | English |
|---|---|
| Pages (from-to) | 1131-1135 |
| Number of pages | 5 |
| Journal | Science |
| Volume | 354 |
| Issue number | 6316 |
| DOIs | |
| State | Published - Dec 2 2016 |
| Externally published | Yes |
Funding
M.A.J. and K.D.J. acknowledge financial support from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award Numbers DE-FG02-06ER15800 and DE-FG02-06ER15066. K.D.J. acknowledges the use of resources in the University of Pittsburgh's Center for Simulation and Modeling. A.B.M. thanks the U.S. NSF (grant CHE-1619660) and the Ohio Supercomputing Center for resources on the Oakley Cluster. M.R.F. and K.R.A. acknowledge financial support from Collaborative Research Center 1109 of the German Research Foundation (Deutsche Forschungsgemeinschaft). Additional data supporting the conclusions are available in supplementary materials.