title: Quantum-chemical study of CHCl3-SO2 association.
abstract: CHCl(3)-SO(2) association is studied by high-level quantum-chemical calculations of stationary points of the dimer electronic potential-energy hypersurface, including correlated second-order Moller-Plesset and CCSD(T) calculations with basis sets up to 6-311++G(d,p). During geometry optimization, frequency, and energy calculations, a self-written computer code embedding the GAMESS ab initio program suite applies counterpoise correction of the basis set superposition error. A CH...O hydrogen-bonded complex (DeltaE(0)=-8.73 kJmol) with a 2.4 A intermolecular H...O distance and two very weak van der Waals complexes (DeltaE(0)=-3.78 and -2.94 kJmol) are located on the counterpoise-corrected potential-energy surface. The intermolecular interactions are characterized by Kitaura-Morokuma interaction energy decompositions and Mulliken electron population analyses. The unusual hydrogen bond is distinguished by a CH-bond contraction, a pronounced enhancement of the IR intensity and a shift to higher frequency ("blueshift") of the CH-stretching vibration compared to the CHCl(3) monomer. Spectroscopy and association in liquid solution is also discussed; our results provide an alternative explanation for features in the CH-stretching vibration spectrum of chloroform dissolved in liquid sulfur dioxide which have been attributed previously to an intermolecular Fermi resonance.
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom. m.hippler@sheffield.ac.uk
authors.forename: Michael
authors.initials: M
authors.lastname: Hippler
mesh_terms: D000465:Algorithms; D002627:Chemistry, Physical / Q000379:methods*; D002725:Chloroform / Q000737:chemistry*; D003198:Computer Simulation; D019281:Dimerization; D004581:Electronics; D006860:Hydrogen Bonding; D011789:Quantum Theory; D012984:Software; D013055:Spectrophotometry, Infrared / Q000379:methods; D013458:Sulfur Dioxide / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D013458:Sulfur Dioxide; D002725:Chloroform