Journal article
Ab initio spectroscopic characterization of the HNNO and ONHN radicals
The Journal of chemical physics, Vol.134(8), pp.084308-084308-10
02/24/2011
Handle:
https://hdl.handle.net/2376/105853
PMID: 21361540
Abstract
A composite coupled cluster methodology is used with systematic sequences of correlation consistent basis sets to accurately determine the structure, vibrational frequencies, and isotopic shifts for
trans
-HNNO (
2
A
′
),
cis
-HNNO (
2
A
′
), and ONHN (
2
A
′
). Anharmonic corrections to the vibrational frequencies and rotational constants are obtained using density functional theory. With basis sets larger than double-zeta, large differences between restricted open-shell Hartree-Fock (ROHF)-based and unrestricted Hartree-Fock (UHF)-based coupled cluster harmonic frequencies are calculated, with the UHF-based ones judged to be more reliable based on an analysis of the orbital hessian eigenvalues. The final calculated anharmonic vibrational band origins are generally in good agreement with the experimental values measured in rare gas matrices. The calculation of the vibrational band origins of the isovalent NO
2
molecule at similar levels of theory exhibits an agreement with experiment to within a few wavenumbers. In the latter case, however, a ROHF treatment was required since the UHF approach failed to provide realistic frequencies for the antisymmetric stretching mode. The heat of formation at 0 K of
trans
-HNNO is calculated to be 50.5 ± 0.5 kcal/mol using a very similar composite coupled cluster methodology as in the structure and harmonic frequency determinations.
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Details
- Title
- Ab initio spectroscopic characterization of the HNNO and ONHN radicals
- Creators
- Kirk Peterson - Department of Chemistry, Washington State University, Pullman, Washington 99164, USAJoseph Francisco - Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
- Publication Details
- The Journal of chemical physics, Vol.134(8), pp.084308-084308-10
- Academic Unit
- Chemistry, Department of
- Publisher
- American Institute of Physics
- Identifiers
- 99900546892601842
- Resource Type
- Journal article