jp8b03645_si_001.txt (59.25 kB)
Download fileCharacterization of OCS–HCCCCH and N2O–HCCCCH Dimers: Theory and Experiment
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posted on 2018-05-29, 00:00 authored by A. J. Barclay, A. Pietropolli Charmet, K. H. Michaelian, N. Moazzen-AhmadiThe
infrared spectra of the weakly bound dimers OCS–HCCCCH,
in the region of the ν1 fundamental band of OCS (2050
cm–1), and N2O–HCCCCH, in the
region of the ν1 fundamental band of N2O (2200 cm–1), were observed in a pulsed supersonic
slit jet expansion probed with tunable diode/QCL lasers. Both OCS–HCCCCH
and N2O–HCCCCH were found to have planar structure
with side-by-side monomer units having nearly parallel axes. These
bands have hybrid rotational structure which allows for estimates
of the orientation of OCS and N2O in the plane of their
respective dimers. Analogous bands for OCS–DCCCCD and N2O–DCCCCD were also observed and found to be consistent
with the normal isotopologues. Various levels of theoretical calculations
were performed to find stationary points on the potential energy surface,
optimized structures, and interaction energies. Four stable geometries
were found for OCS–HCCCCH and three for N2O–HCCCCH.
The rotational parameters at CCSD(T*)-F12c level of theory give results
in very good agreement with those obtained from the observed spectra.
In both dimers, the experimental structure corresponds to the lowest
energy isomer.