Computational thermochemistry of oxygenated polycyclic aromatic hydrocarbons and relevant radicals

Tairan Wang, Kiran K. Yalamanchi, Xin Bai, Shuyuan Liu, Yang Li*, Bei Qu, Goutham Kukkadapu, S. Mani Sarathy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Oxygenated polycyclic aromatic hydrocarbons (OPAHs) have attracted growing attention due to their toxicological harmfulness and significant role in soot formation. This study comprehensively investigates the thermochemistry of OPAH species and relevant radicals via quantum-chemical calculations. Temperature-dependent enthalpy of formation, entropy, and heat capacity for C5[sbnd]C18 OPAHs (59 molecules and 33 radicals) are consistently determined at the M06–2X/6-311++G(d,p) level of theory. Considerable differences are found to be introduced by different methods when calculating electronic energies, and the G3 method outperforms the composite compound methods G3/G4/CBS-APNO. The calculated thermochemical properties from the G3 method show excellent agreement with literature data. An accurate thermochemistry database for OPAHs is thus developed. In addition, the existing group additivity (GA) method does not apply to OPAHs since the group additivity values (GAVs) derived from small hydrocarbons fail to predict large polycyclic species. Based on our dataset, GAVs are obtained from combinatorial considerations. The updated GAVs can be applied with enhanced confidence to estimate the thermochemical parameters at different temperatures for larger OPAHs where such high-accuracy quantum chemistry calculations are intractable. These thermodynamic properties and GAVs are crucial for the development of accurate kinetic models for OPAH formation chemistry and for achieving emission control.

Original languageEnglish (US)
Article number112484
JournalCombustion and Flame
StatePublished - Jan 2023


  • Group additivity
  • Oxygenated polycyclic aromatic hydrocarbons
  • Quantum chemistry calculations
  • Soot formation
  • Thermochemistry

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • General Physics and Astronomy


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