Influence of mass and potential energy surface geometry on roaming in Chesnavich's CH${}_4^{+}$ model

Abstract

Chesnavich's model Hamiltonian for the reaction CH${}_4^{+}\to$ CH${}_3^{+}$ is known to exhibit a range of interesting dynamical phenomena including roaming. The model system consists of two parts: a rigid, symmetric top representing the CH${}_3^{+}$ ion and a free H atom. We study roaming in this model with focus on the evolution of geometrical features of the invariant manifolds in phase space that govern roaming under variations of the mass of the free atom m and a parameter a that couples radial and angular motion. In addition, we establish an upper bound on the prominence of roaming in Chesnavich's model. The bound highlights the intricacy of roaming as a type of dynamics on the verge between isomerisation and nonreactivity as it relies on generous access to the potential wells to allow reactions as well as a prominent area of high potential that aids sufficient transfer of energy between the degrees of freedom to prevent isomerisation.

References in corpus (2)

• Phase space barriers and dividing surfaces in the absence of critical points of the potential energy: Application to roaming in ozone
• The phase space geometry underlying roaming reaction dynamics

Cited by in corpus (5)

• Using Lagrangian descriptors to uncover invariant structures in Chesnavich's Isokinetic Model with application to roaming
• Roaming at Constant Kinetic Energy: Chesnavich's Model and the Hamiltonian Isokinetic Thermostat
• Predicting trajectory behaviour via machine-learned invariant manifolds
• Phase space structures causing the reaction rate decrease in the collinear hydrogen exchange reaction
• Roaming in acetaldehyde