Thirty-five years ago I was a postgraduate student at the University of East Anglia and in the middle of the research for my doctorate. In simple terms I was looking at how metal-compounds interact to quench light-driven chemical and physical processes in organic compounds; this was done using pulses of laser light which typically lasted millionths of a second (a technique called laser flash photolysis). The technique was already well characterised and the metal-induced photochemical quenching already of industrial importance in developing additives to make plastics more light stable – after all one doesn’t want buckets or sinks which fall apart after a short while as happened in the chemistry labs at University of York when I was an undergraduate there. In our research we were extending the work to try to better understand the physics of the systems at a quantum energy level, and (as my supervisor memorably expressed it) fill in one piece of the jigsaw puzzle which is photosynthesis – the chemical and physical processes by which plants turn water, carbon dioxide and light into energy, sugars, proteins and oxygen; the veritable bedrock of life. It was but a very tiny piece of a massive jigsaw puzzle and to this day I still do not understand how it earned me a doctorate!
This was at the time when Lord Porter (then Professor Sir George Porter) who won a Nobel prize for the invention of flash-photolysis was at the Royal Institution and was just beginning to develop systems using picosecond lasers which we thought at the time was mind-blowing. (A picosecond is one million-millionth of a second, so around a million time shorter than the equipment I was using).
Thirty-five years on scientists are now on the threshold of putting in the very last pieces of that jigsaw. This at least is the way I read today’s BBC News item which describes scientists watching the reacting electrons in the molecules using a similar photolysis technique but with laser pulses lasting just 100 femtoseconds, that’s one ten-thousandth of a billionth of a second (or ten thousand million times shorter than an average camera flash). I’m not so much gobsmacked at the rate of technological innovation – one has almost come to expect that – but more that not only has this been done but that it is possible to achieve such incredibly fast pulses of light AND use them to watch chemical reactions in such real-time detail. It is something we dreamt of doing but never imagined would become a reality. For me this is much more gobsmacking science than any piece of cosmology or particle accelerator physics.
