Full-dimensional potential energy surface development and dynamics for the HBr + C₂H₅ → Br(²P_3/2) + C₂H₆ reaction

Abstract

We report a full-dimensional spin-orbit-corrected analytical potential energy surface (PES) for the HBr + C2H5 → Br + C2H6 reaction and a quasi-classical dynamics study on the new PES. For...

Automated full-dimensional potential energy surface development and quasi-classical dynamics for the HI(X1Σ+) + C2H5 → I(2P3/2) + C2H6 reaction

“…The preference of forward scattering is more obvious in the HI + C2H5 reaction than in HBr + C2H5. 9 This finding indicates a direct stripping mechanism for HI + C2H5 at every Ecoll. The title reaction favors H-side attack over side-on HI and the least-preferred Iside approach, as expected, because an H-C bond forms in the abstraction process, and favors side-on CH3CH2 attack over CH2-side and the least-preferred CH3-side approach at high Ecoll.…”

“…It is clear that energy flow in the HI + C2H5 system is also very similar to the case in the HBr + C2H5 system, except that the reaction energy of HI + C2H5 is larger than that of HBr + C2H5 (35 vs 19 kcal/mol). 9 Rotational energy distributions are cold and blue-shift as Ecoll increases. The corresponding rotational quantum numbers span ranges of about 0-60 and 0-120 at the lowest and highest collision energies, respectively, as Fig.…”

“…Following the same strategy applied previously for the HBr + C 2 H 5 reaction, 9 the initial candidate of the geometry set of the HI + C 2 H 5 reaction is obtained by randomly displacing the Cartesian coordinates of the stationary points 35 in the 0–0.4 Å interval. In addition, the displaced reactants and products are randomly scattered around each other in the range of 3–8 Å.…”

“…As a class of elementary reactions, atom transfer or metathesis reactions of HX + C 2 H 5 ↔ X + C 2 H 6 (X = F, Cl, Br, I) have become benchmark systems to study the dynamics and mechanisms of post-six-atom polyatomic chemical reactions. These exothermic reactions have attracted a lot of attention from both experiment and theory for the forward processes (X = Br, I) 1–9 and backward processes (X = F, Cl), 10–34 whose activation energies have been found to have small positive or negative values. 35…”

“…34 A full-dimensional spin–orbit-corrected analytical PES for the HBr + C 2 H 5 reaction and a quasi-classical dynamics study on the new PES were reported very recently. 9…”