title: The infrared spectrum of the Ne-C2D2 complex.
abstract: Infrared spectra of Ne-C2D2 are observed in the region of the ν3 fundamental band (asymmetric C-D stretch, ≈2440 cm(-1)) using a tunable optical parametric oscillator to probe a pulsed supersonic slit jet expansion from a cooled nozzle. Like helium-acetylene, this system lies close to the free rotor limit, making analysis tricky because stronger transitions tend to pile up close to monomer (C2D2) rotation-vibration transitions. Assignments are aided by predicted rotational energies calculated from a published ab initio intermolecular potential energy surface. The analysis extends up to the j = 3←2 band, where j labels C2D2 rotation within the dimer, and is much more complete than the limited infrared assignments previously reported for Ne-C2H2 and Ne-C2HD. Two previous microwave transitions within the j = 1 state of Ne-C2D2 are reassigned. Coriolis model fits to the theoretical levels and to the spectrum are compared. Since the variations observed as a function of C2D2 vibrational excitation are comparable to those noted between theory and experiment, it is evident that more detailed testing of theory will require vibrational averaging over the acetylene intramolecular modes.
authors.affiliation: Department of Physics and Astronomy, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Moazzen-Ahmadi
authors.affiliation: National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada.
authors.forename: A R W
authors.initials: AR
authors.lastname: McKellar
authors.affiliation: Department of Physical Chemistry and Center for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Berta
authors.initials: B
authors.lastname: Fernández
authors.affiliation: Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
authors.forename: David
authors.initials: D
authors.lastname: Farrelly