When molecules collide there are two possibilities. They can bounce apart--relatively unaltered by the contact--with the same atoms bound together in the same structure. Another possibility is that the molecules react; the atoms that make up the colliding molecules are reshuffled by exchanging partners, so that the molecules are transformed into new molecules, new substances.
What led to my Nobel Prize in chemistry in 1986 was my fresh look at chemical reactions. Instead of trying to answer the prevalent question of the day, which focussed on the effect of concentration and temperature on reaction rates, I asked another question: What types of forces, operating during a molecular collision, lead to a chemical reaction?
Finding an answer has not been simple. How do you coax two molecules in mid-collision to reveal their secrets to you? How do you physically measure the different types of motion involved in a molecular reaction? I can show you how the method of infrared chemiluminescence, which I developed, was able to measure the feeble infrared emission from a newly-formed molecule, and thus provide us with an understanding of how the newborn molecules vibrate and rotate, and hence what forces are operating when they are born.
As so often happens, this new understanding led to new devices; in this instance, a large category of lasers based on vibrating molecules. These lasers are the most powerful sources of infrared radiation in existence, and yet they came from studying emission so feeble it could barely be detected. In other words, by seeking a new understanding of molecular reactions, one of the world's most significant technologies was born. And that is the power of fundamental science
