Dynamics of Coulomb explosion and kinetic energy release in clusters of heterocyclic compounds

The studies presented herein elucidate details of the Coulomb explosion event initiated through the interaction of heterocyclic clusters with an intense femtosecond laser beam (greater than or equal to1 PW/cm(2)). Clusters studied include 7-azaindole and pyridine. Covariance analysis verifies that the fragmentation channels are competitive. Kinetic-energy analyses, from experiment and simulation, suggest that Coulomb exploded fragments are created with varying amounts of energy and have a strong mass-to-charge relationship. Backward-ejected protons are found to impact the repeller and eject adsorbed protons from the surface. Moreover, delayed fragmentation is suggested by fast-Fourier transformation of a proton time-of-flight mass spectrum and confirmed by deconvoluting the aforementioned signal through intensity decrements. Voltage gradient, laser power, and microchannel plate detector studies yield insight into the solvation effect of clusters in the Coulomb explosion event. Conceptually, the dynamic charge resonance enhanced ionization (Dynamic CREI) model best explains these results of heterocyclic Coulomb explosion. (C) 2002 American Institute of Physics.