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Title: Ab initio study of the CO/sub 2/ dimer and the CO/sub 2/ ion complexes (CO/sub 2/)/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/

Abstract

Ab initio calculations were performed at several levels for neutral CO/sub 2/, CO/sub 2/ dimer, and the cations (CO/sub 2/)/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/. At the highest level, a CO/sub 2/ neutral dimer of C/sub 2h/ symmetry (staggered side-by-side) is bound by 1.3 kcal/mol, which is 0.2 kcal/mol more stable than a T-shaped dimer (C/sub 2v/ symmetry). The dissociation energy of a (CO/sub 2/)/sub 2//sup +/ complex of C/sub 2h/ symmetry is calculated to be 16.2 kcal/mol which is 4.4 kcal/mol greater than the dissociation energy of the T-shaped (CO/sub 2/)/sub 2//sup +/ complex. Due to a smaller amount of spin contamination (spin polarization), the stability of this complex which is characterized by a partial bond between oxygens is overestimated at the (MP4SDQ/6-31G*) level relative to the T-shaped ion complex and CO/sub 2//sup +/ (plus CO/sub 2/) which have significant spin contamination. Projecting out the largest spin contaminant at the PMP2/6-31G* level and at the PMP4/3-21G level leads to an estimated decrease in the energy separation between the C/sub 2h/ symmetry complex and the T-shaped complex of 6.3 kcal/mol (relative to the (MP4SDQ/6-31G*) method). Two trimers of (CO/sub 2/)/sub 3//sup +/ were considered, a cyclic complex (C/submore » 3h/) and a cross-shaped complex (D/sub 2h/). The more stable (CO/sub 2/)/sub 3//sup +/ complex (D/sub 2h/) is bound by 16.0 kcal/mol with respect to monomers. Vibrational frequencies were used to compute entropies of reaction for (CO/sub 2/)/sub 2//sup +/ ..-->.. CO/sub 2/ + CO/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/ ..-->.. 2CO/sub 2/ + CO/sub 2//sup +/.« less

Authors:
; ;
Publication Date:
Research Org.:
Auburn Univ., AL
OSTI Identifier:
6193090
Resource Type:
Journal Article
Journal Name:
J. Phys. Chem.; (United States)
Additional Journal Information:
Journal Volume: 91:13
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 54 ENVIRONMENTAL SCIENCES; CARBON DIOXIDE; DISSOCIATION ENERGY; ENTHALPY; ENTROPY; SPECIFIC HEAT; VIBRATIONAL STATES; CALCULATION METHODS; CATIONS; COMPLEXES; DIMERS; IONIZATION POTENTIAL; THEORETICAL DATA; THERMODYNAMICS; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHARGED PARTICLES; DATA; ENERGY; ENERGY LEVELS; EXCITED STATES; INFORMATION; IONS; NUMERICAL DATA; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; THERMODYNAMIC PROPERTIES; 400201* - Chemical & Physicochemical Properties; 500100 - Environment, Atmospheric- Basic Studies- (-1989)

Citation Formats

Illies, A J, McKee, M L, and Schlegel, H B. Ab initio study of the CO/sub 2/ dimer and the CO/sub 2/ ion complexes (CO/sub 2/)/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/. United States: N. p., 1987. Web. doi:10.1021/j100297a007.
Illies, A J, McKee, M L, & Schlegel, H B. Ab initio study of the CO/sub 2/ dimer and the CO/sub 2/ ion complexes (CO/sub 2/)/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/. United States. https://doi.org/10.1021/j100297a007
Illies, A J, McKee, M L, and Schlegel, H B. 1987. "Ab initio study of the CO/sub 2/ dimer and the CO/sub 2/ ion complexes (CO/sub 2/)/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/". United States. https://doi.org/10.1021/j100297a007.
@article{osti_6193090,
title = {Ab initio study of the CO/sub 2/ dimer and the CO/sub 2/ ion complexes (CO/sub 2/)/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/},
author = {Illies, A J and McKee, M L and Schlegel, H B},
abstractNote = {Ab initio calculations were performed at several levels for neutral CO/sub 2/, CO/sub 2/ dimer, and the cations (CO/sub 2/)/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/. At the highest level, a CO/sub 2/ neutral dimer of C/sub 2h/ symmetry (staggered side-by-side) is bound by 1.3 kcal/mol, which is 0.2 kcal/mol more stable than a T-shaped dimer (C/sub 2v/ symmetry). The dissociation energy of a (CO/sub 2/)/sub 2//sup +/ complex of C/sub 2h/ symmetry is calculated to be 16.2 kcal/mol which is 4.4 kcal/mol greater than the dissociation energy of the T-shaped (CO/sub 2/)/sub 2//sup +/ complex. Due to a smaller amount of spin contamination (spin polarization), the stability of this complex which is characterized by a partial bond between oxygens is overestimated at the (MP4SDQ/6-31G*) level relative to the T-shaped ion complex and CO/sub 2//sup +/ (plus CO/sub 2/) which have significant spin contamination. Projecting out the largest spin contaminant at the PMP2/6-31G* level and at the PMP4/3-21G level leads to an estimated decrease in the energy separation between the C/sub 2h/ symmetry complex and the T-shaped complex of 6.3 kcal/mol (relative to the (MP4SDQ/6-31G*) method). Two trimers of (CO/sub 2/)/sub 3//sup +/ were considered, a cyclic complex (C/sub 3h/) and a cross-shaped complex (D/sub 2h/). The more stable (CO/sub 2/)/sub 3//sup +/ complex (D/sub 2h/) is bound by 16.0 kcal/mol with respect to monomers. Vibrational frequencies were used to compute entropies of reaction for (CO/sub 2/)/sub 2//sup +/ ..-->.. CO/sub 2/ + CO/sub 2//sup +/ and (CO/sub 2/)/sub 3//sup +/ ..-->.. 2CO/sub 2/ + CO/sub 2//sup +/.},
doi = {10.1021/j100297a007},
url = {https://www.osti.gov/biblio/6193090}, journal = {J. Phys. Chem.; (United States)},
number = ,
volume = 91:13,
place = {United States},
year = {Thu Jun 18 00:00:00 EDT 1987},
month = {Thu Jun 18 00:00:00 EDT 1987}
}