Theoretical study of the excitation function in the CN + C2H6 hydrogen transfer reaction. Effect of vibrational excitation

TL;DR

This theoretical study uses quasi-classical trajectory calculations to analyze the excitation function of the CN + C2H6 hydrogen transfer reaction, revealing how vibrational excitation influences the reaction dynamics and energy dependence.

Contribution

It provides a detailed theoretical analysis of the reaction's excitation function and the effect of vibrational excitation using full-dimensional potential energy surface calculations.

Findings

Reaction is highly exothermic and nearly barrierless.

Excitation functions exhibit a V-shape profile.

Vibrational excitation affects the impact parameter and reaction dynamics.

Abstract

To gain insight into the dynamics of the CN + C2H6 gas-phase reaction, quasi-classical trajectory (QCT) calculations were performed on a full-dimensional analytical potential energy surface. This reaction presents very high exothermicity, -22.20 kcal/mol, and it is practically barrierless, with a barrier height of 0.23 kcal/mol, being an early transition state reaction. The V-shape form of the excitation function is characteristic of non-threshold reactions. The pronounced increase observed at lower energies can be attributed to the substantial increase in the impact parameter within this energy regime. Vibrational excitations by one quantum of stretching and bending modes give rise to excitation functions that present a similar V-shaped profile.