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Title: Communication: Spectroscopic consequences of proton delocalization in OCHCO{sup +}

Even though quartic force fields (QFFs) and highly accurate coupled cluster computations describe the OCHCO{sup +} cation at equilibrium as a complex between carbon monoxide and the formyl cation, two notable and typical interstellar and atmospheric molecules, the prediction from the present study is that the equilibrium C{sub ∞v} structure is less relevant to observables than the saddle-point D{sub ∞h} structure. This is the conclusion from diffusion Monte Carlo and vibrational self-consistent field/virtual state configuration interaction calculations utilizing a semi-global potential energy surface. These calculations demonstrate that the proton “rattle” motion (ν{sub 6}) has centrosymmetric delocalization of the proton over the D{sub ∞h} barrier lying only 393.6 cm{sup −1} above the double-well OCHCO{sup +} C{sub ∞v} minima. As a result, this molecule will likely appear D{sub ∞h}, and the rotational spectrum will be significantly dimmer than the computed equilibrium 2.975 D center-of-mass dipole moment indicates. However, the proton transfer fundamental, determined to be at roughly 300 cm{sup −1}, has a very strong intensity. This prediction as well as those of other fundamentals should provide useful guides for laboratory detection of this cation. Finally, it is shown that the two highest energy QFF-determined modes are actually in good agreement with theirmore » vibrational configuration interaction counterparts. These high-level quantum chemical methods provide novel insights into this fascinating and potentially common interstellar molecule.« less
Authors:
 [1] ; ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Department of Chemistry, Georgia Southern University, Statesboro, Georgia 30460 (United States)
  2. Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)
  3. NASA Ames Research Center, Moffett Field, California 94035-1000 (United States)
  4. Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061 (United States)
  5. Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138 (United States)
  6. Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)
Publication Date:
OSTI Identifier:
22493525
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON MONOXIDE; CATIONS; CENTER-OF-MASS SYSTEM; COMPLEXES; CONFIGURATION INTERACTION; DIFFUSION BARRIERS; DIPOLE MOMENTS; EQUILIBRIUM; FORMYL RADICALS; MOLECULAR IONS; MOLECULES; MONTE CARLO METHOD; POTENTIAL ENERGY; PROTONS; SELF-CONSISTENT FIELD; SURFACES; VIBRATIONAL STATES; VIRTUAL STATES