TY - JOUR TI - Benchmark Ab Initio Characterization of the Abstraction and Substitution Pathways of the Cl + CH3CN Reaction ID - publicatio24762 SP - 2802 A1 - Tóth Petra A1 - Sz?cs Tímea A1 - Czakó Gábor N1 - Export Date: 20 June 2022 CODEN: JPCAF Correspondence Address: Czakó, G.; MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Rerrich Béla tér 1, Hungary; email: gczako@chem.u-szeged.hu Funding details: Magyar Tudományos Akadémia, MTA Funding details: Emberi Eroforrások Minisztériuma, EMMI, 20391-3/2018/FEKUSTRAT, TKP2021-NVA-19 Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIH, K-125317 Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA, TKP2021-NVA Funding text 1: We thank the National Research, Development and Innovation Office?NKFIH, K-125317; the Ministry of Human Capacities, Hungary grant 20391-3/2018/FEKUSTRAT; project no. TKP2021-NVA-19, provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme; and the Momentum (Lendület) Program of the Hungarian Academy of Sciences for financial support. AV - public JF - JOURNAL OF PHYSICAL CHEMISTRY A N2 - We investigate the reaction pathways of the Cl + CH3CN system: hydrogen abstraction, methyl substitution, hydrogen substitution, and cyanide substitution, leading to HCl + CH2CN, ClCN/CNCl + CH3, ClCH2CN + H, and CH3Cl + CN, respectively. Hydrogen abstraction is exothermic and has a low barrier, whereas the other channels are endothermic with high barriers. The latter two can proceed via a Walden inversion or front-side attack mechanism, and the front-side attack barriers are always higher. The C-side methyl substitution has a lower barrier and also a lower endothermicity than the N-side reaction. The computations utilize an accurate composite ab initio approach and the explicitly correlated CCSD(T)-F12b method. The benchmark classical and vibrationally adiabatic energies of the stationary points are determined with the most accurate CCSD(T)-F12b/aug-cc-pVQZ energies adding further contributions of the post-(T) and core correlation, scalar relativistic effects, spin-orbit coupling, and zero-point energy corrections. These contributions are found to be non-negligible to reach subchemical accuracy. Š SN - 1089-5639 UR - http://doi.org/10.1021/acs.jpca.2c01376 EP - 2810 Y1 - 2022/// IS - 18 VL - 126 ER -