Complex Formation during SID and Its Effect on Proton Mobility

Surface-induced dissociation (SID) of protonated peptides is a vibrant, active field of study. Significant focus has been placed on understanding the mechanism of dissociation, with most approaches using equilibrium thermodynamic arguments. Here, we explore the dynamics of SID using atomistic simulations. We find that it is common for complexes of peptide fragments to form following dissociation. An important consequence of complexation is that excess protons are not isolated following initial fragmentation and can participate in subsequent chemical reactions. Our work reveals an alternate mechanism for proton mobility that, to our knowledge, has not been previously observed in simulations.