Coulomb fission in multiply charged molecular clusters: Experiment and theory

Harris, Christopher; Baptiste, Joshua; Lindgren, Eric B.; Besley, Elena; Stace, Anthony J.

Abstract

A series of three multiply charged molecular clusters, (C6H6)nz+ (benzene), (CH3CN)nz+ (acetonitrile), and (C4H8O)nz+ (tetrahydrofuran), where the charge z is either 3 or 4, have been studied for the purpose of identifying patterns of behaviour close to the charge instability limit. Experiments show that on a time scale of ~10-4 s, ions close to the limit undergo Coulomb fission where all of the observed pathways exhibit considerable asymmetry in the sizes of the charged fragments, and are associated with kinetic (ejection) energies of between 1.4 and 2.2 eV. Accurate kinetic energies have been determined through a computer simulation of peak profiles recorded in the experiments and the results modelled using a theory formulated to describe how charged particles of dielectric materials interact with one another (Bichoutskaia et al. J. Chem. Phys. 2010, 133, 024105). The calculated electrostatic interaction energy between separating fragments gives an accurate account for the measured kinetic energies and also supports the conclusion that +4 ions fragment into +3 and +1 products as opposed to the alternative of two +2 fragments. This close match between theory and experiment supports the assumption that a significant fraction of excess charge resides on the surfaces of the fragment ions. It is proposed that the high degree of asymmetry seen in the fragmentation patterns of the multiply charged clusters is due, in part, to limits imposed by the time window during which observations are made.

Citation

Harris, C., Baptiste, J., Lindgren, E. B., Besley, E., & Stace, A. J. (2017). Coulomb fission in multiply charged molecular clusters: Experiment and theory. Journal of Chemical Physics, 146(16), Article 164302. https://doi.org/10.1063/1.4981918

• Journal Article Type: Article
• Acceptance Date: Apr 10, 2017
• Online Publication Date: Apr 25, 2017
• Publication Date: Apr 28, 2017
• Deposit Date: May 9, 2017
• Publicly Available Date: May 9, 2017
• Journal: Journal of Chemical Physics
• Print ISSN: 0021-9606
• Electronic ISSN: 1089-7690
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 146
• Issue: 16
• Article Number: 164302
• DOI: https://doi.org/10.1063/1.4981918
• Public URL: https://nottingham-repository.worktribe.com/output/857453
• Publisher URL: http://aip.scitation.org/doi/10.1063/1.4981918
• Additional Information: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in The Journal of Chemical Physics 146, 164302 (2017) and may be found at http://aip.scitation.org/doi/10.1063/1.4981918.
• Contract Date: May 9, 2017