Fig. 1.

The average of the symmetrized PT coordinates for pairs of consecutive PT events (double PT jumps) on the x axis vs. the collective compression of the wire on the y axis. On the x axis, and are the symmetrized PT coordinates defined as the difference in distance of the transferring proton along the hydrogen bond [ and ]. The species O(1), O(2), and O(3) are consecutive oxygen atoms along a wire that house the proton at some point during PT. Associated with each PT coordinate is the distance between the oxygen atoms along the wire: , , and the y axis shows the sum of these two distances. This plot is strikingly similar to the “banana” plots in the stepwise PT jumps (9). Here, instead double jumps are facilitated by collective compressions (see SI Appendix for similar plot for the extent of correlations in groups of triple PT events).