Detection of a higher energy isomer of the CO-N2O van der Waals complex and determination of two of its intermolecular frequencies

A J Barclay; C Lauzin; S Sheybani-Deloui; K H Michaelian; N Moazzen-Ahmadi

doi:10.1039/c6cp08001d

Detection of a higher energy isomer of the CO-N₂O van der Waals complex and determination of two of its intermolecular frequencies

Phys Chem Chem Phys. 2017 Jan 4;19(2):1610-1613. doi: 10.1039/c6cp08001d.

Authors

A J Barclay¹, C Lauzin², S Sheybani-Deloui¹, K H Michaelian³, N Moazzen-Ahmadi¹

Affiliations

¹ Department of Physics and Astronomy, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4, Canada. nmoazzen@ucalgary.ca.
² Institute of Condensed Matter and Nanosciences (IMCN), Université catholique de Louvain, Louvain-la-Neuve, Belgium. clement.lauzin@uclouvain.be.
³ Natural Resources Canada, CanmetENERGY in Devon, 1 Oil Patch Drive, Suite A202, Devon, Alberta T9G 1A8, Canada.

PMID: 27991939
DOI: 10.1039/c6cp08001d

Abstract

Infrared spectra in the carbon monoxide CO stretch region (∼2150 cm^-1) and in the ν₃ asymmetric stretch region of N₂O (∼2223 cm^-1) are assigned to the previously unobserved O-bonded form of the CO-N₂O dimer ("isomer 2"). This van der Waals complex has a planar skewed T-shaped structure like that of the previously observed C-bonded form ("isomer 1"), but with the CO rotated by 180°. The effective intermolecular distance between the centers of mass is 3.51 Å for isomer 2 as compared to 3.88 Å for isomer 1. In addition to the fundamental band, two combination bands are observed for isomer 2, yielding values for two intermolecular vibrational modes: 14.502(5) cm^-1 for the coupled disrotatory motion or the uncoupled CO rock and 21.219(5) cm^-1 for the out-of-plane rock. We show that the published ab initio study on this system is inadequate in predicting the intermolecular frequencies for isomer 2 of CO-N₂O.