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Title: Investigating the Ground-State Rotamers of n-Propylperoxy Radical

The n-propylperoxy radical has been described as a molecule of critical importance to studies of low temperature combustion. Ab initio methods were used to study this three-carbon alkylperoxy radical, normal propylperoxy. Reliable CCSD(T)/ANO0 geometries were predicted for the molecule's five rotamers. For each rotamer, energetic predictions were made using basis sets as large as the cc-pV5Z in conjunction with coupled cluster levels of theory up to CCSDT(Q). Along with the extrapolations, corrections for relativistic effects, zero-point vibrational energies, and diagonal Born--Oppenheimer corrections were used to further refine energies. The results indicate that the lowest conformer is the gauche-gauche (GG) rotamer followed by the gauche-trans (0.12 kcal mol^-1 above GG), trans-gauche (0.44 kcal mol^-1), gauche'-gauche (0.47 kcal mol^-1), and trans-trans (0.57 kcal mol^-1). Fundamental vibrational frequencies were obtained using second-order vibrational perturbation theory (VPT2). This is the first time anharmonic frequencies have been computed for this system. The most intense IR features include all but one of the C-H stretches. The O-O fundamental (1063 cm^-1 for the GG structure) also has a significant IR intensity, 19.6 km mol^-1. The anharmonicity effects on the potential energy surface were also used to compute vibrationally averaged r_g,0 K bond lengths, accounting for zero-point vibrationsmore » present within the molecule.« less
Authors:
 [1] ;  [1] ;  [1]
  1. Univ. of Georgia, Athens, GA (United States). Center for Computational Quantum Chemistry
Publication Date:
OSTI Identifier:
1329476
Grant/Contract Number:
FG02-97ER14748
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 145; Journal Issue: 17; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of Georgia, Athens, GA (United States). Center for Computational Quantum Chemistry
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS Peroxy Radicals; Low-Temperature Combustion