Influence of mass and potential energy surface geometry on roaming in Chesnavich’s CH4+ model

Vladimír Krajňák, Stephen Wiggins*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

6 Citations (Scopus)
237 Downloads (Pure)


Chesnavich’s model Hamiltonian for the reaction CH4+→ CH3+ + H 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 CH3+ 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.

Original languageEnglish
Article number094109
JournalJournal of Chemical Physics
Issue number9
Early online date7 Sept 2018
Publication statusPublished - 25 Oct 2018


  • math.DS
  • physics.chem-ph


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