The Born-Oppenheimer approximation simplifies the Schrodinger equation into more manageable pieces (unlike physicists, some of us have to deal with more than one electron…) and is pretty crucial for quantum chemistry. It doesn’t always hold, however, but in some complicated physical chemistry we let Gav write about, it still holds up in reactions between hydrogen and chlorine.
Seeing as one day nanoscale people will be driving around in nanoscale cars, it’s worth making sure that they won’t be breaking the 2nd law of thermodynamics. Fortunately for everyone, it doesn’t look like they will: a classical mechanical ratchet on the molecular scale just slows down, rather than going in one direction.
Molecular knots are normally tricky beasts to make – as you might expect – but now a method to make some by simply allowing silver ions and organic ligands to diffuse together takes only one step. Different length ligands produce different knots.
Neil Withers (Associate Editor, Nature Chemistry)