There’s a neat little story on Nature News today about measuring the speed of electrons. Apparently, this group has done sensitive X-ray measurements of the movements of electrons in and around atoms. It’s pretty cool – it takes about 150 attoseconds (150 billion billion billion billion billion billionths of a second. I think.) for it to “orbit” around the nucleus, and 320 attoseconds to jump from a sulphur atom to a ruthenium (a typle of metal) surface nearby.
What I don’t completely understand is how they track the movement of the electron. See, in quantum mechanics electrons aren’t solid little cricket balls or anything like that – there’s uncertainty in where they are, and even how fast they’re moving. You really need to think of them as little “clouds” of electrons, where the electron is actually everywhere within the cloud at once. (Don’t worry – three or four (or five or six) years of quantum mechanics will make that a lot more understandable… :)) So they actually had to watch for the whole probability cloud to move between atoms, by looking at how the X-rays they sent in were absorbed. So it’s pretty neat!
You might be wondering why they were doing this. Well electron movement is critical for many (all?) chemical reactions, and if we can better understand how the electrons move we might be better placed for designing new compounds that perform a specific task (e.g., catalysts to speed up reactions, or perhaps certain drugs). They’re also trying to look for differences between electrons with different spins (think of it as a basketball spinning clockwise or anticlockwise). This is working towards a spintronics where computers run not on 1s and 0s but on spin “up”s and “down”s. The hope is that this would lead to faster, smaller and more efficient computers. (Note that it’s also different to quantum computers that you may have heard of. These will be classical computers, that do what our current computers do now, just better.)