Head of Discipline for Chemistry

Valeria Arrighi

 

Staff by Sections

Inorganic Chemistry

Alan Welch

Jan-Willem Bos

James Cameron

Scott Dalgarno

Gareth Lloyd

Stuart Macgregor

Stephen Mansell 

Ruaraidh McIntosh

Organic Chemistry

Dave Adams

Euan Brown

Graeme Barker

Magnus Bebbington

Nicola Howarth

Arno Kraft

Ai-Lan Lee

Nick Leslie

Kevin McCullough

Colin Rickman

Filipe Vilela

Physical Chemistry

Ken McKendrick

Valeria Arrighi

David Bucknall

Matt Costen

Stuart Greaves

Maciej Gutowski

Martin McCoustra

N Hendrik Nahler

Martin Paterson

Experimental Officers and Administrative Staff

Dave Ellis

Georgina Rosair

Placement Coordinators

Industrial:  Scott Dalgarno

Honorary and Emeritus Staff

John Parker

Joe Pfab

Matt Costen

MA, DPhil, MRSC

Professor

Telephone
+44 (0)131 451 8197
Email
m.l.costen@hw.ac.uk
Address
Room G.31
William Perkin Building
Heriot-Watt University
Roles and responsibilities
  • Chemistry Postgraduate Research Coordinator
  • EPS Postgraduate Research Coordination Group
  • Perkin Building Laser Safety Officer
Research

 

Dynamics and Kinetics of Molecular Collisions

Collisions between molecules resulting in energy transfer or reaction are the fundamental interactions of chemistry. The research in my group is aimed at deepening our understanding of these elementary steps, and uses the unique properties of lasers to prepare and probe the reagents and products. This work is carried out jointly with Prof Ken McKendrick (see our joint research group webpages).

1. Stereodynamics of Gas-Phase Collisions

Measurement of vector properties (the stereodynamics) of gas-phase collisions are a sensitive probe of the forces involved. We use a variety of sensitive spectroscopic techniques to study collisional energy transfer, in particular crossed molecular beams with velocity-map ion-imaging and frequency modulated spectroscopy (figure 1). We interpret the results with the help of quantum scattering calculations, often performed by collaborators in other institutions..

Figure 1. Velocity-map ion-images of NO(A2S+, N') scattered from Ne in a crossed-beam apparatus, for different probe laser polarizations. The variation in intensity reflects changing rotational polarization as a function of scattering angle..

2. Roaming Atoms and Molecules

A new dynamical channel in molecular photodissociation has recently been identified, in which an atomic or molecular fragment ‘roams’ around its partner before reacting to form the products. The signature of a roaming channel appears in the coincident product state distribution. We have recently built a new velocity-map imaging spectrometer (figure 2), with the aim of identifying how common roaming reactions really are. This is in collaboration with Dr David Townsend (IPaQS) and Dr Stuart Greaves (ICS).

Figure 2. The newly constructed velocity-map imaging spectrometer, with the detector and flight tube pointing towards the camera..

3. Dynamics at the Gas-Liquid Interface

The dynamics of the elementary steps occurring at gas-liquid interfaces has seen very little study, despite their fundamental importance in atmospheric, combustion and other environments. This work, led by Prof Ken McKendrick, studies the inelastic and reactive collisions of OH radicals and oxygen atoms (figure 3) at surfaces that mimic atmospheric aerosols, or are of technological importance e.g. ionic liquids..

Figure 3. O(3P) atoms are formed by photolysis, fly to the liquid covered surface of a rotating wheel, and the returning OH radicals are probed by laser-induced fluorescence.

 

Selected publications

Up-to-date publications are listed on this research profile.

Further information

Dynamics and Kinetics of Molecular Collisions