In general, the world of chemistry is a closed book. Reactions happen, and my understanding is limited to counting electrons and seeing if they add up. Despite this ignorance, there is a particular field of chemistry that I really love: photochemistry, or chemistry driven by light. Nothing gives me more pleasure than setting stuff on fire with a laser—I mean carefully studying light-controlled reactions.
Seriously though, there is this whole field out there where chemists and physicists study and control reactions using light. Or, more accurately, they study how to control the breakup of molecules using light fields. These experiments make use of something called coherent control, where we use light to steer electrons. As a result, the light controls the chemistry. But creating molecules using the same idea has proven to be hard—really hard. That makes a recent publication on the creation of molecules using coherent control reasonably important.
One of the easier—and I use that word in the sense of "not impossible"—demonstrations of coherent control involves tearing molecules apart. The reason this is easy is because as long as your laser is powerful enough, you can always tear molecules apart. That means you can always start with a light pulse that does the job, then by tweaking the pulse shape (more on that below), you can increase the efficiency with which you break molecules. Or, you can aim to break particular bonds.
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