Triple ionization and fragmentation of benzene trimers following ultrafast intermolecular Coulombic decay

Abstract

Intermolecular interactions involving aromatic rings are ubiquitous in biochemistry and they govern the properties of many organic materials. Nevertheless, our understanding of the structures and dynamics of aromatic clusters remains incomplete, in particular for systems beyond the dimers, despite their high presence in many macromolecular systems such as DNA and proteins. Here, we study the fragmentation dynamics of benzene trimer that represents a prototype of higher-order aromatic clusters. The trimers are initially ionized by electron-collision with the creation of a deep-lying carbon 2s−1 state or one outer-valence and one inner-valence vacancies at two separate molecules. The system can thus relax via ultrafast intermolecular decay mechanisms, leading to the formation of C$${}_{6}{{{{{{{{{\rm{H}}}}}}}}}_{6}}^{+}\cdot$$ 6 H 6 + ⋅ C$${}_{6}{{{{{{{{{\rm{H}}}}}}}}}_{6}}^{+}\cdot$$ 6 H 6 + ⋅ C$${}_{6}{{{{{{{{{\rm{H}}}}}}}}}_{6}}^{+}$$ 6 H 6 + trications and followed by a concerted three-body Coulomb explosion. Triple-coincidence ion momentum spectroscopy, accompanied by ab-initio calculations and further supported by strong-field laser experiments, allows us to elucidate the details on the fragmentation dynamics of benzene trimers.

Two-Sided Impact of Water on the Relaxation of Inner-Valence Vacancies of Biologically Relevant Molecules

“…As a result, two cation-radical monomers repelling each other and a low-energy electron are produced (Figure ). The ICD was first predicted theoretically by Cederbaum and co-workers in 1997 and later confirmed experimentally in a large variety of atomic and molecular clusters. − The process is proved to take place on an ultrashort time scale (usually in the femtosecond regime), , and contrary to the local decay mechanisms, its efficiency increases with the number of neighbors in the environment. , …”

A double ouroboros-shaped noncovalent molecular dimer

“…These three fused benzene units are arranged like a symmetrical cyclic aromatic trimer (CAT) structure. 9,11,12 The data suggest that aromatic edge-to-face interactions are present in the CAT motif in TEt . A closer look into the structure of TEt reveals that the CAT motif actually lies above the face of the phenyl spacer.…”

Revealing the Role of N Heteroatoms in Noncovalent Aromatic Interactions by Ultrafast Intermolecular Coulombic Decay

“…In addition, the sequential ionization should take place mainly when the intermolecular bonds align along the direction of the electron beam. Therefore, the contribution of sequential ionization is minor (<10% according to ref 40).…”

“…This is an ultrafast decay mechanism occurring on a femtosecond time scale. − It leads to the formation of a charge-delocalized dicationic dimer, which undergoes a two-body Coulomb explosion reaction. This ultrafast process provides a direct means for probing the structures of molecular complexes. − Our studies aim to explore the structural preferences of these fundamental dimers by multiparticle coincidence momentum imaging of the ICD processes , and, thus, to elucidate the influence of the N heteroatoms on the intermolecular interactions between aromatic rings depending on the number of N heteroatoms in the systems.…”