High-level analytical potential-energy-surface-based dynamics of the OH⁻ + CH₃CH₂Cl S_N2 and E2 reactions in full (24) dimensions

Abstract

We develop a coupled-cluster full-dimensional global potential energy surface (PES) for the OH− + CH3CH2Cl reactive system, using the ROBOSURFER program package, which automatically samples configurations along PES-based trajectories as...

Dynamics of the HCl + C2H5 Multichannel Reaction on a Full-Dimensional Ab Initio Potential Energy Surface

“…The theoretical dynamical investigation of systems containing more than six atoms on full-dimensional analytical potential energy surfaces (PESs) has only become feasible in the recent decade(s). − Following the extensive literature on atom + H 2 O/CH 4 reactions, − the atom + C 2 H 6 reactions have emerged as the new benchmark systems, − which represent several new possibilities and also many challenges for reaction dynamics studies: (1) rules of thumb discovered for small/medium-sized reactions can be extended for polyatomic reactivity, (2) these reactions often involve multiple competitive reaction channels, calling for sophisticated PES development techniques, and (3) with the increasing number of degrees of freedom, mode- and bond-selectivity are of major interest in these complex systems. Many of such investigations have enriched our knowledge in recent years, using quasi-classical trajectory (QCT) computations.…”

“…Following initial QCT studies of atom + ethane reactions on force-field-based PESs, , high-quality ab initio potential energy surfaces have been developed by our group for different reactions of ethane, using an automated improvement strategy, providing excellent agreement with dynamics experiments regarding the HF/HCl product rotational and/or vibrational distributions for the F and Cl + C 2 H 6 reactions, , and mode-specific vibrational populations of H 2 O in the OH + ethane reaction . Other polyatomic reactions, such as O­( 3 P) + C 2 H 4 , OH + CH 4 , H/F/Cl/OH + CH 3 OH, − OH – + CH 3 F/CH 3 I, ,, F – (H 2 O)/Cl – (H 2 O) + CH 3 I, Cl + propene/pentane, , F – /OH – + CH 3 CH 2 Cl, , NH 2 – + CH 3 I, HBr/HI + C 2 H 5 , , H 2 O/NH 3 + CH 2 OO, , F/Cl + CH 3 NH 2 , , and F – + (CH 3 ) 3 CI, have also been the subjects of QCT simulations, and vibrational and rotational mode-specificity have been explored in several of these postsix-atomic systems. Additionally, reduced-dimensional quantum dynamics computations have also been performed for such polyatomic reactions. − …”