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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Is HO3 minimum cis or trans? An analytic full-dimensional ab initio isomerization path.
1Departmento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal. varandas@qtvs1.qui.uc.pt
Physical Chemistry Chemical Physics : PCCP
|April 14, 2011
Summary
This study reveals that the trans-HO(3) isomer is more stable than the cis-HO(3) isomer, challenging previous predictions. Accurate ab initio calculations confirm this finding, providing crucial insights into HO(3) isomerization.
Area of Science:
- Quantum Chemistry
- Theoretical Chemistry
- Computational Chemistry
Background:
- Understanding the relative stability of isomers is crucial in chemical dynamics.
- Previous theoretical studies on HO(3) isomerization yielded conflicting results regarding the more stable isomer.
- Experimental data on HO(3) rovibrational spectroscopy exists but is incomplete.
Purpose of the Study:
- To accurately determine the minimum energy pathway for HO(3) isomerization.
- To definitively identify the more stable isomer of HO(3) (cis vs. trans).
- To provide a theoretical foundation for analyzing experimental rovibrational data.
Main Methods:
- High-level ab initio methods, including coupled-cluster and multireference configuration interaction.
- Extrapolation techniques to the complete basis set limit for high accuracy.
- Development of a scheme to model the isomerization potential-energy surface.
Main Results:
- The trans-HO(3) isomer is predicted to be more stable than the cis-HO(3) isomer, aligning with experimental evidence.
- Energy differences between isomers are small, less than 1 kcal mol(-1).
- Inclusion of zero-point energy further stabilizes the trans isomer.
Conclusions:
- Systematic ab initio calculations confirm the greater stability of the trans-HO(3) isomer.
- The developed modeling scheme can aid in interpreting experimental spectroscopic data.
- This work resolves a long-standing ambiguity in the theoretical understanding of HO(3) isomerization.
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