@article{ram_depompa_westmoreland_2024, title={Thermochemistry of Gas-Phase Thermal Oxidation of C<sub>2</sub> to C<sub>8</sub> Perfluorinated Sulfonic Acids with Extrapolation to C<sub>16</sub>}, volume={4}, ISSN={["1520-5215"]}, url={https://doi.org/10.1021/acs.jpca.4c01208}, DOI={10.1021/acs.jpca.4c01208}, abstractNote={New ideal-gas thermochemistry Cp°(T), H°(T), S°(T), and G°(T) are predicted for 53 species involved in the thermal destruction of perfluorinated sulfonic acids (PFSAs) ranging from C2 to C8 in perfluorinated alkyl chain length. Species were selected by considering both the pyrolytic and oxidative pathways of PFSA destruction. After the sulfur-containing moieties are removed, subsequent reactions largely involve species from a prior set of thermochemistry for the thermal destruction of perfluorinated carboxylic acids (Ram et al., J. Phys. Chem. A, 2024, 128, 7, 1313–1326). Enthalpies of formation at 0 K are computed using a new isogyric reaction scheme. Rigid-rotor harmonic-oscillator partition functions were calculated over a 200–2500 K temperature range using rovibrational properties at G4 (≤C3S1 species) and M06-2X-D3(0)/def2-QZVPP (≥C4S1 species), employing the 1D hindered rotor approximation to correct for torsional modes. Seven-coefficient NASA polynomial fits are reported in standardized formats. Bond dissociation energies and important reaction equilibria are examined to provide insights into the reactivity of potentially persistent species. Extrapolated NASA polynomials are also systematically predicted for 126 species larger than C8/C8S1 in size, allowing reasonably accurate estimates of thermochemistry without the need for expensive electronic structure calculations.}, journal={JOURNAL OF PHYSICAL CHEMISTRY A}, author={Ram, Hrishikesh and DePompa, C. Murphy and Westmoreland, Phillip R.}, year={2024}, month={Apr} }
 @article{ram_sadej_murphy_mallo_westmoreland_2024, title={Thermochemistry of Species in Gas-Phase Thermal Oxidation of C<sub>2</sub> to C<sub>8</sub> Perfluorinated Carboxylic Acids}, volume={2}, ISSN={["1520-5215"]}, url={https://doi.org/10.1021/acs.jpca.3c06937}, DOI={10.1021/acs.jpca.3c06937}, abstractNote={New thermochemical properties, Cp°(T), H°(T), S°(T), and G°(T), are predicted for 123 species involved in the thermal destruction of perfluorinated carboxylic acids (PFCAs) using computational quantum chemistry and ideal-gas statistical mechanics. Relevant species were identified from the development of mechanisms for the pyrolysis and oxidation of PFCAs of C2 to C8 in length. Partition functions were obtained from the results of calculations at the G4 level for species up to C4 in length and M06-2X-D3(0)/def2-QZVPP for species C5 to C8 in length. The 1D hindered-rotor approximation was used to correct for torsional modes in the larger species. Ideal-gas thermochemistry was computed and fitted to 7-parameter NASA polynomials over a 200-2500 K temperature range, and the data are provided in standardized format. To gauge the effects of both method and basis set choice, enthalpies of formation at 0 K are calculated from various other density functionals (including B3LYP and ωB97XD), basis sets, and composite model chemistries (CBS-QB3). They are benchmarked against data from the Active Thermochemical Tables, high-level ANL0 calculations from the literature, and G4 calculations from this work. The effects of internal rotations and other anharmonicities are discussed, and bond dissociation energies and reaction equilibria provide mechanistic insights.}, journal={JOURNAL OF PHYSICAL CHEMISTRY A}, author={Ram, Hrishikesh and Sadej, Thomas P. and Murphy, C. Claire and Mallo, Tim J. and Westmoreland, Phillip R.}, year={2024}, month={Feb} }