High-resolution Infrared Diode Laser Spectroscopy of (CO20)3 : Vibrationally averaged structures, resonant dipole vibrational shifs, and tests of CO2-CO2 pair potentials

Published

July 1, 1995

Author(s)

M J. Weida, J M. Sperhac, David Nesbitt

Abstract

High-resolution infrared spectra of (CO₂)₃ formed in a split jet supersonic expansion are obtained via direct absoption of a tunable diode laser in the V₃ asymmetric stretch region of CO₂. Over 100 distinct transions are recorded in the trimer spectrum, which can be modeled as a perpendicular band of a planar symmetric top with C_3b symmetry and no observable tunneling splittings. Results from the spectroscopic fit indicate that the complex is vibrationally averaged planar, with a carbon-carbon atom separation of R_cc=4.0376(2) A. An anysis of the vibrational blue shift for (CO₂)₃ of 2.5755(2) cm^-1 via a resonant dipole-dipole interaction model of the equilateral triangle connecting the center of mass of each CO₂ monomer. Several model CO₂-CO₂ interaction potentials are tested monomers within the trimer. Lastly, spectral evidence and model preidctions suggest that there is an asymmetric top isomer of the trimer that is energetically comparable to the observed cyclic isomer.

Citation

Journal of Chemical Physics

Volume

103

Issue

No. 18

Pub Type

Journals

Keywords

(CO₂)₃, CO₂ trimer, complexes, diode laser, high resolution, supersonic, van der Waals

Citation

Weida, M. , Sperhac, J. and Nesbitt, D. (1995), High-resolution Infrared Diode Laser Spectroscopy of (CO₂0)₃ : Vibrationally averaged structures, resonant dipole vibrational shifs, and tests of CO₂-CO₂ pair potentials, Journal of Chemical Physics (Accessed May 10, 2024)