ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The resonant two-photon ionization spectra of the first benzene–Arn (n≤8) clusters are interpreted in the light of a model calculation, including local energy minima determinations and Monte Carlo simulations. Based on spectral shift information, two types of structures are distinguished: the argon cluster either only solvates one side of the substrate molecule or covers simultaneously both sides. The "wettest'' structures are assigned to sandwich-type forms for n≤4 and to clamshell-type forms beyond. Such a 2D–3D transition in the n=5–8 size range is shown to be specific to small substrate size. In the one-sided forms, the argon cluster geometry is strongly influenced by the presence of the Bz molecule since it adopts a quasiplanar geometry, more or less tightly bound to the substrate depending on its size: the small argon clusters exhibit two types of complexation sites (c and s forms) which are simultaneously visited (surface decoupling) even at low temperature (∼7 K). As the size increases, the c form becomes prevalent and the surface decoupling becomes inhibited. At n=8 a 2D–3D transition is observed: beyond the n=7 species, characterized by a caplike close-packed structure, the one-sided conformers disappear in favor of bridged forms. Additional results on the ionization behavior of the one-sided species show regular variation of the ionization potential with the cluster size.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.464849
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