Roaming: Dynamical Reaction Pathways in Phase Space
S. Wiggins, School of Mathematics, University of Bristol
Quoting from a well-known article of Bowman and Suits (J. M. Bowman and A. G.
Suits, Roaming Reactions :The Third Way, Physics Today, 64(11), 33 (2011)):
Only until very recently it was believed that chemical reactions can occur only
by two fundamental ways: i) dissociation over a potential energy barrier and
ii) stretching of a bond until it breaks. However, in 2004 a “third way” was
discovered, which has been given the name “roaming”..
In my talk I will discuss the idea of “roaming” from a phase space perspective. In
particular, roaming is described as an alternate reaction pathway in phase space that
is guided by specific types of phase space structures. I will illustrate this by
considering roaming in formaldehyde and demonstrating the existence of the phase
space structures that “select” between roaming and dissociating trajectories. If time
permits, I will discuss the generality of this approach and roaming in other systems
(e.g. ketene isomerization, ion-molecule reactions).
An underlying theme of my talk is the tremendous opportunities in chemistry for
applied and computational mathematics, to contribute both new mathematics and new
chemistry. Along these lines I will comment on some of the challenges facing
mathematicians that seek to enter this field.
All of the ideas in this talk were developed in collaboration with Peter Collins and
Frederic Mauguiere (University of Bristol), Gregory S. Ezra and Zeb Kramer (Cornell
University), Stavros Farantos (University of Crete), Barry Carpenter (Cardiff
University). This work was supported by the UK Engineering and Physical Sciences
Research Council, the US National Science Foundation, the Leverhulme Trust, and
the US Office of Naval Research.