Dynamics of the Cl− + CH3I reaction on a high-level ab initio analytical potential energy surface
We have developed a full-dimensional analytical ab initio potential energy surface (PES) for the Cl− + CH3I reaction using the Robosurfer program system. The energy points have been computed using a robust composite method defined as CCSD-F12b + BCCD(T) – BCCD with the aug-cc-pVTZ(-PP) basis set and...
Elmentve itt :
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| Dokumentumtípus: | Cikk |
| Megjelent: |
2023
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| Sorozat: | JOURNAL OF CHEMICAL PHYSICS
158 No. 19 |
| Tárgyszavak: | |
| doi: | 10.1063/5.0151259 |
| mtmt: | 34034585 |
| Online Access: | http://publicatio.bibl.u-szeged.hu/30084 |
| Tartalmi kivonat: | We have developed a full-dimensional analytical ab initio potential energy surface (PES) for the Cl− + CH3I reaction using the Robosurfer program system. The energy points have been computed using a robust composite method defined as CCSD-F12b + BCCD(T) – BCCD with the aug-cc-pVTZ(-PP) basis set and have been fitted by the permutationally invariant polynomial approach. Quasi-classical trajectory simulations on the new PES reveal that two product channels are open in the collision energy (Ecoll) range of 1–80 kcal/mol, i.e., SN2 leading to I− + CH3Cl and iodine abstraction (above ∼45 kcal/mol) resulting in ICl− + CH3. Scattering angle, initial attack angle, product translational energy, and product internal energy distributions show that the SN2 reaction is indirect at low Ecoll and becomes direct-rebound–back-side (CH3-side) attack-type, as Ecoll increases. Iodine abstraction mainly proceeds with direct stripping mechanism with side-on/back-side attack preference. Comparison with crossed-beam experiments and previous direct dynamics simulations shows quantitative or qualitative agreement and also highlights possible theoretical and/or experimental issues motivating further research. |
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| Terjedelem/Fizikai jellemzők: | 8 |
| ISSN: | 0021-9606 |