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Title: A density functional tight binding/force field approach to the interaction of molecules with rare gas clusters: Application to (C{sub 6}H{sub 6}){sup +/0}Ar{sub n} clusters

We propose in the present paper a SCC-DFTB/FF (Self-Consistent-Charge Density Functional based Tight Binding/Force-Field) scheme adapted to the investigation of molecules trapped in rare gas environments. With respect to usual FF descriptions, the model involves the interaction of quantum electrons in a molecule with rare gas atoms in an anisotropic scheme. It includes polarization and dispersion contributions and can be used for both neutral and charged species. Parameters for this model are determined for hydrocarbon-argon complexes and the model is validated for small hydrocarbons. With the future aim of studying polycyclic aromatic hydrocarbons in Ar matrices, extensive benchmark calculations are performed on (C{sub 6}H{sub 6}){sup +/0}Ar{sub n} clusters against DFT and CCSD(T) calculations for the smaller sizes, and more generally against other experimental and theoretical data. Results on the structures and energetics (isomer ordering and energy separation, cohesion energy per Ar atom) are presented in detail for n = 1–8, 13, 20, 27, and 30, for both neutrals and cations. We confirm that the clustering of Ar atoms leads to a monotonous decrease of the ionization potential of benzene for n ⩽ 20, in line with previous experimental and FF data.
Authors:
; ; ; ;  [1]
  1. Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse (France)
Publication Date:
OSTI Identifier:
22255279
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ARGON COMPLEXES; BENZENE; CHARGE DENSITY; DENSITY FUNCTIONAL METHOD; INTERACTIONS; POLARIZATION; POLYCYCLIC AROMATIC HYDROCARBONS