Bringing astronomy down to earth

1 November 2011

Quantemol

Analysing starlight seems about as far removed from solving problems here on earth as it’s possible to get. ‘Astronomical spectroscopy is a long way ahead of applicability,’ admits UCL’s Professor Jonathan Tennyson. ‘I’m a blue-sky physicist. And yet my work has more subtle applications than you might imagine.’

One focus is on what Tennyson calls ‘very hot water’ – very hot indeed. The fusion process that powers stars leads either to a carbon- or an oxygen-rich solar environment. Water vapour arises in the latter case when oxygen combines with the star’s hydrogen. Researchers at UCL have identified water not only in these oxygen-rich stars and in comets, but also in planets beyond our solar system, unknown when they began the research. To their surprise, they also found it around carbon stars, a finding which overturned previous assumptions about the relative abundance of the two elements.

Grounded theory

The research turns out to have relevance to terrestrial problems as well. The water spectra can be used for the early detection of forest fires, for example. Connections like these underline the value of theoretical physics. ‘Our latest list has 500 million water spectral lines. You couldn’t hope to measure them all. So I’d argue the only way forward is to build a really robust theoretical model,’ says Tennyson.

Although his own work involves the fundamental quantum mechanics that govern molecular interactions, Tennyson tries to pick problems where his contribution might have practical use. One application where it is especially important to know about these collisions is in the plasma etching processes used to make integrated circuits. ‘The etching industry is based on empiricism – it’s like cooking.’ Manufacturing tends to rely on chef-like skill as much as science. Yet it is hugely expensive. ‘So it’s clear that if you can gain an insight into where to go on theoretical grounds, you can make real progress.’

Computer modelling

Tennyson now leads a project, which aims, using a computer program, to model what happens in processes involving electron collisions with gas phase molecules. It is available as freeware on his website, but with Dan Brown, ‘entrepreneur in residence’ at UCL’s Computer Science Department, he has also set up a company, Quantemol. With funding from NESTA, Quantemol has developed an expert system to run the code for commercial clients.

One company that recognized the superiority of Tennyson’s modelling is Surface Technology Systems (now SPTS), which used the program in its own manufacturing and has worked with Tennyson on subsequent versions, which are being developed with help from UCL Business. Leslie Lea, formerly chief scientist at STS, found Tennyson ‘the stereotypical professor in that he was very excited about the work’ but also ‘good at recognizing where an idea can be used in a different field.’

IMAGE: Water vapour in the atmosphere of a star. Credits: NASA, ESA, RAS, UCL, G. Bacon (STScI), Dan Durda, Andy McLatchie & Sylvain Girard