Gas-phase thermochemistry of polycyclic aromatic hydrocarbons: an approach integrating the quantum chemistry composite scheme and reaction generator. Issue 5 (18th January 2022)

• Record Type: Journal Article
• Authors: Minenkova, Irina; Otlyotov, Arseniy A.; Cavallo, Luigi; Minenkov, Yury
• Is Part Of: Physical chemistry chemical physics. Volume 24:Issue 5(2022)
• Page Start: 3163
• Page End: 3181
• Publication Date: 2022-01-18
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d1cp03702a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : A protocol aimed at reducing the dependence of the calculated gas-phase enthalpies of formation on a particular chemical reaction is introduced. It is further utilized to predict the gas-phase thermochemistry of 113 polycyclic aromatic hydrocarbons. Abstract : We introduce a protocol aimed at predicting the accurate gas-phase enthalpies of formation of polycyclic aromatic hydrocarbons (PAHs). Automatic generation of a dataset of equilibrated chemical reactions preserving the number of carbon atoms in each hybridization state on each side of equations is at the core of our scheme. The performed tests suggest the recommended enthalpy of formation to be derived via a two-step scheme. First, we consider the reactions with a minimal sum of the total number of particles involved, N, and the absolute difference between the total number of products and reactants, |Δ N |. Second, among these reactions, we identify the one with the smallest absolute reaction enthalpy change, . This approach has been applied to predict the gas-phase enthalpies of formation of 113 PAHs via the Feller–Peterson–Dixon approach. Our calculated values provide the mean absolute deviations of 1.7, 1.9, 4.2, 8.1, and 18.5 kJ mol −1 with respect to the literature group-based error corrected (GBEC) G3MP2B3, ATOMIC (HC), group equivalent M06-2X, GBEC B3LYP, and G4MP2 values. Our predicted values give the mean signed and mean absolute errors of −7.5 and 12.9 kJ mol −1 with respect to the experimental enthalpies of formation. The combination of our predicted and the experimental values provide the solid-state enthalpies of formation, , which are not available for a few species. Approaching these values as well as, producing large discrepancies from the experimental side, would be indispensable for testing and further tuning of computational chemistry approaches.