Protons within thin water layers

When the dye in the thin water layer is laser pulsed, its proton is rapidly ejected and, after rapid relaxation to ground state, an ion pair H+ and 4>0 is formed. The strong absorption of the 4>0 anion (at 450 nm) fades rapidly (within a few microseconds) due to its reaction with the proton, and the system relaxes to its initial prepulse state. Typical traces are shown in Figure 1. The two traces correspond to recombination in unstressed vesicles, where the width of the water layer is 25 A, and under strong osmotic pressure (applied by sucrose), which squeezes the water layer to 10 A (7). Both signals exhibit a rise time, unresolved at that time frame, followed by well-resolved relaxation. 

---