AI identifies molecules from their featureless visible spectrum

An artificial intelligence algorithm can identify molecules from their visible spectrum, where many organic compounds are completely transparent and have no absorption peaks to speak of. ‘Forget about the peaks – that’s the main result,’ says Felipe Herrera from the University of Santiago, Chile. Once the algorithm is trained on more structure, as well as mixtures, it could enhance non-destructive optical sensing to identify explosives or environmental contaminants.

When it comes to detecting molecules by probing them with a laser, ‘infrared (IR) spectroscopy is said to be so precise that nothing can beat it‘, Herrera says. The fingerprint region in IR or Raman spectra can be used by chemists and machines alike to pinpoint which molecule they are looking at. But the instruments needed to get these spectra are bulky, expensive and need an expert user, says Ross Gillanders, who works on optical sensors at the University of St Andrews, UK. ‘The advantage of using visible light is that you can really reduce the cost of a field device and potentially make it a lot more portable and user friendly as well,‘ he points out.