Martin Karplus, Michael Levitt and Arieh Warshel won this year’s Nobel Prize in chemistry on Wednesday for laying the foundation for the computer models used to understand and predict chemical processes.

The Royal Swedish Academy of Sciences said their research in the 1970s has helped scientists develop programs that unveil chemical processes such as the purification of exhaust fumes or the photosynthesis in green leaves. “The work of Karplus, Levitt and Warshel is ground-breaking in that they managed to make Newton’s classical physics work side-by-side with the fundamentally different quantum physics,” the academy said. “Previously, chemists had to choose to use either/or.” Karplus, a U.S. and Austrian citizen, is affiliated with the University of Strasbourg, France, and Harvard University. The academy said Levitt is a British, U.S., and Israeli citizen and a professor at the Stanford University School of Medicine. Warshel is a U.S. and Israeli citizen affiliated with the University of Southern California in Los Angeles. Warshel told a news conference in Stockholm by telephone that he was “extremely happy” to be awakened in the middle of the night in Los Angeles to find out he had won the prize and looks forward to collecting the award in the Swedish capital in December. “In short what we developed is a way which requires computers to look, to take the structure of the protein and then to eventually understand how exactly it does what it does,” Warshel said. Earlier this week, three Americans won the Nobel Prize in medicine for discoveries about how key substances are moved around within cells and the physics award went to British and Belgian scientists whose theories help explain how matter formed after the Big Bang. The Noble Committee Prize Announcement The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry for 2013 to Martin Karplus (Université de Strasbourg, France and Harvard University, Cambridge, MA, USA), Michael Levitt (Stanford University School of Medicine, Stanford, CA, USA), and Arieh Warshel (University of Southern California, Los Angeles, CA, USA) “for the development of multiscale models for complex chemical systems” The computer—your Virgil in the world of atoms Chemists used to create models of molecules using plastic balls and sticks. Today, the modelling is carried out in computers. In the 1970s, Martin Karplus, Michael Levitt and Arieh Warshel laid the foundation for the powerful programs that are used to understand and predict chemical processes. Computer models mirroring real life have become crucial for most advances made in chemistry today. Chemical reactions occur at lightning speed. In a fraction of a millisecond, electrons jump from one atomic nucleus to the other. Classical chemistry has a hard time keeping up; it is virtually impossible to experimentally map every little step in a chemical process. Aided by the methods now awarded with the Nobel Prize in Chemistry, scientists let computers unveil chemical processes, such as a catalyst’s purification of exhaust fumes or the photosynthesis in green leaves. The work of Karplus, Levitt and Warshel is ground-breaking in that they managed to make Newton’s classical physics work side-by-side with the fundamentally different quantum physics. Previously, chemists had to choose to use either or. The strength of classical physics was that calculations were simple and could be used to model really large molecules. Its weakness, it offered no way to simulate chemical reactions. For that purpose, chemists instead had to use quantum physics. But such calculations required enormous computing power and could therefore only be carried out for small molecules. This year’s Nobel Laureates in chemistry took the best from both worlds and devised methods that use both classical and quantum physics. For instance, in simulations of how a drug couples to its target protein in the body, the computer performs quantum theoretical calculations on those atoms in the target protein that interact with the drug. The rest of the large protein is simulated using less demanding classical physics. Today the computer is just as important a tool for chemists as the test tube. Simulations are so realistic that they predict the outcome of traditional experiments.