Roaming at Constant Kinetic Energy: Chesnavich's Model and the Hamiltonian Isokinetic Thermostat

TL;DR

This paper investigates the roaming reaction mechanism under constant kinetic energy constraints using Chesnavich's model and finds that roaming persists despite nonholonomic constraints, with dynamics similar to unconstrained Hamiltonian systems.

Contribution

It demonstrates that roaming dynamics occur under nonholonomic isokinetic constraints, extending understanding of reaction mechanisms in constrained Hamiltonian systems.

Findings

Roaming persists under constant kinetic energy constraints.

The roaming mechanism's origin is similar to unconstrained Hamiltonian systems.

Nonholonomic constraints do not inhibit roaming dynamics.

Abstract

We consider the roaming mechanism for chemical reactions under the nonholonomic constraint of constant kinetic energy. Our study is carried out in the context of the Hamiltonian isokinetic thermostat applied to Chesnavich's model for an ion-molecule reaction. Through an analysis of phase space structures we show that imposing the nonholonomic constraint does not prevent the system from exhibiting roaming dynamics, and that the origin of the roaming mechanism turns out to be analogous to that found in the previously studied Hamiltonian case.