Phenol-water clusters ionized

The proton transfer in ionized phenol-water clusters is strongly dependent on the number of water molecules and their specific organization, i.e., the PT is a process assisted by the solvent [72], Most of the theoretical studies of PT in [C6H50H-(H20) ],+ clusters were focused on the structure, vibrational, [79,80,81] and energetic aspects [77,78]. However, much less is known on the dynamics of PT. 

Born-Oppenheimer molecular dynamics simulations for neutral and ionized phenol-water clusters are reported. The results for [C6H50D-(H20)4],+ illustrate how the PT dynamics is coupled to fluctuations of the solvent. The kinetics of PT/recombination in [C6H50D-(H20)4] + clusters is related to strong fluctuations of the electrostatic field of the water molecules and this relationship points out the relevance of investigating the electronic properties of the HB network for understanding chemical reaction in solution. 

The time evolution of the phenol O—D distance between the phenolic oxygen and the deuterium and the D-Ow distance between the deuterium and the oxygen of the nearest water molecule in the neutral (left panel at the bottom) and ionized clusters (right panels) is shown in Figure 5-6. 

The time evolution of the O—D and D—Ow distances in the ionized clusters is also shown in Figure 5-6 (A-H right panels). In contrast with the neutral system, significant changes of the distances can be observed. These variations describe the occurrence of proton transfer from the phenolic moiety to water and also recombination of the transferred proton with the phenoxy moiety. As expected, the PT dynamics is dependent on the initial configuration. 

Figure 5-6. Time evolution of the O—D distance (full lines) between the phenol oxygen and the deuterium and the D—Ow distance (dotted lines) between the PhOD deuterium and the oxygen of the nearest water molecule in the neutral (left panel at the bottom) and ionized clusters (A-H right panels). The t = 0 time corresponds to the ionization of the [C5H5OD—(IhOb cluster at different (A-H) equilibrium configurations. The snapshots show for each trajectory the structure of the [C HsOD—(fyO) ] cluster corresponding to the configuration where the O—D and D—Ow distances are the same before the first PT following ionization...

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