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Massey University INMS scientist Associate Professor John Harrison specialises in spectroscopy and molecular dynamics. This includes development of techniques for aligning and orienting molecules for the investigation of stereodynamic effects in molecular collisions.
It is in the latter where his interest and skills met a project led by Prof Richard N Zare and his group in the Chemistry Department at Stanford University.
Using lasers to probe chemical reactions
The group is using lasers to probe one of the simplest chemical reactions – the reaction of hydrogen atoms with hydrogen molecules. Associate Professor Harrison’s experimental expertise has been his key input, assisting in the attempts to orient hydrogen molecules so that the hydrogen atom can be collided either in a side-on or end-on manner with the hydrogen molecule. The process needs a sequence of intense laser pulses to orient the hydrogen molecules, laser pulses that are 5 billionths of a second long and need to be coordinated to within a fraction of that time for the process to be effective. The reaction is then initiated about 10 billionths of a second after that and the products detected a short time later. All this requires several state of the art, high-powered tunable laser systems and is done under very high vacuum conditions.
One of only two laboratories
“The group at Stanford has been pre-eminent in pioneering laser based methods for chemical stereodynamics – the influence on the chemical reaction of relative orientation of the reactants – and in building a system which can successfully make this theory work. Only two laboratories are capable of doing this type of experiment; the one in Stanford, USA and one in China, so it’s fantastic to have the opportunity to be involved.
Thirty years ago Prof. Zare was on the board of the Miller Institute at the University of California, Berkeley where Dr Harrison was a postdoctoral (Miller) fellow. This connection led, thirty years later, to Dr Harrison spending half of 2008 on sabbatical at Stanford.
“The field of chemical reaction dynamics is very active because of the insights that it brings and the ultimate increase in understanding for all chemical processes that can result. “
“This is one step on the long path to learning how to actively influence the outcome of a chemical reaction by controlling the stereochemistry of the collision.”
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Last updated on Tuesday 16 August 2016