Researchers in California say they've realized every chemist's dream -- to capture an atomic-scale picture of a chemical before and after it reacts.

Chemists and physicists at the University of California, Berkeley, say a state-of-the-art atomic force microscope has allowed them to take the world's first atom-by-atom pictures, including images of the chemical bonds between atoms, capturing how a molecule's structure changes during a reaction.

"Even though I use these molecules on a day-to-day basis, actually being able to see these pictures blew me away. Wow!" chemistry Professor Felix Fischer, the study leader, said. "This was what my teachers used to say that you would never be able to actually see, and now we have it here."

The ability to image molecular reactions in this way will show chemists for the first time the products of their reactions and help them fine-tune the reactions to get the products they want, a Berkeley release said Thursday.

"In chemistry you throw stuff into a flask and something else comes out, but you typically only get very indirect information about what you have," Fischer said. "It is more like a puzzle, putting all the information together and then nailing down what the structure likely is. But it is just a shadow.

"Here we actually have a technique at hand where we can look at it and say this is exactly the molecule," he said. "It's like taking a snapshot of it."