Magnetic resonance is like a tuning fork that rings only at its own note. Each molecule has its own frequency, and from that you can tell what the molecule is and what state it's in. But previously, this tuning fork was listened to through a thick wall: the signal was blurred, and you couldn't make out the exact note.
Physicists from Germany have built a device that listens to molecules at a very strong magnetic field—300,000 times stronger than Earth's. They used a frequency of 396 gigahertz, which is thousands of times higher than that of ordinary microwaves. As a result, the signal became sharp, like a bell strike, not a hum. The linewidth is only 210 billionths of the frequency.
To test the precision, the scientists took a molecule shaped like a soccer ball — a nitrogen atom trapped inside a carbon cage. They measured its magnetic response and got a number accurate to sixteen billionths. Previously, such measurements had an error a hundred times larger.
Now physicists have a tool that sees the finest details of molecular magnetic properties. This will help in chemistry, biology, and medicine — everywhere you need to know exactly how molecules are structured.
A nitrogen atom inside a carbon sphere is like a pea in a soccer ball. Such a molecule is called endohedral and behaves like a tiny magnet that can be caught in resonance.