title: Towards a spectroscopic and theoretical identification of the isolated building blocks of the benzene-acetylene cocrystal.
abstract: Isomer- and mass-selective UV and IR-UV double resonance spectra of the BA3, B2A, and B2A2 clusters of benzene (B) and acetylene (A) are presented. Cluster structures are assigned by comparison with the UV and IR spectra of benzene, the benzene dimer, as well as the BA, BA2, and B2A clusters. The intermolecular vibrations of BA are identified by dispersed fluorescence spectroscopy. Assignment of the cluster structures is supported by quantum chemical calculations of IR spectra with spin-component scaled second-order Møller-Plesset (SCS-MP2) theory. Initial propositions for various structures of the BA3 and B2A2 aggregates are generated with model potentials based on density functional theory combined with the symmetry-adapted perturbation theory (DFT-SAPT) approach. Shape and relative cluster stabilities are then confirmed with SCS-MP2. T-shaped geometries are the dominant structural motifs. Higher-energy isomers are also observed. The detected cluster structures are correlated with possible cluster formation pathways and their role as crystallization seeds is discussed.
authors.affiliation: Institut für Physikalische Chemie, Heinrich-Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Böning
authors.forename: Benjamin
authors.initials: B
authors.lastname: Stuhlmann
authors.forename: Gernot
authors.initials: G
authors.lastname: Engler
authors.forename: Matthias
authors.initials: M
authors.lastname: Busker
authors.forename: Thomas
authors.initials: T
authors.lastname: Häber
authors.forename: Adem
authors.initials: A
authors.lastname: Tekin
authors.forename: Georg
authors.initials: G
authors.lastname: Jansen
authors.forename: Karl
authors.initials: K
authors.lastname: Kleinermanns
mesh_terms: D000114:Acetylene / Q000737:chemistry*; D001554:Benzene / Q000737:chemistry*; D003460:Crystallization; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001554:Benzene; D000114:Acetylene