화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.119, No.44, 10999-11006, 2015
Theoretical Study of the Pyridine-Helium van der Waals Complexes
In this study we evaluate a high-level ab initio ground-state intermolecular potential-energy surface for the pyridine-He van der Waals complex, using the CCSD(T) method and Dunning's augmented correlation consistent polarized valence double-sigma basis set extended with a set of 3s3p2d1f1g midbond functions. The potential is characterized by two symmetric global minima of -93.2 cm(-1) that correspond to geometries where the distance between the helium atom and the pyridine center of mass is 3.105 angstrom and the angle with respect to the pyridine c rotational axis is 3.9 degrees. Six local minima can be observed for geometries with the helium atom in the plane cotaining the pyridine molecule. To further analyze the nature of the intermolecular interactions in the complex, we use symmetry-adapted perturbation theory (SAPT). Additional consideration of the pyridine-He-2 complex provides a better insight into many-body nonadditive contributions to intermolecular interactions in systems with more helium atoms.