STOCKHOLM — Martin Karplus, Michael Levitt and Arieh Warshel won this year's Nobel Prize in chemistry today 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.

That kind of knowledge makes it possible to optimize catalysts for cars, drugs and solar cells, the academy said.

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.

LONDON — A passenger with no flying experience safely landed a light airplane at a British airport after the pilot became incapacitated, officials said today.The plane, carrying two people, issued a mayday call as it returned to the Sandtoft airfield in northeast England on Tuesday evening.Officials at Humberside Airport, near the airfield, put emergency plans into place and successfully helped the passenger land the plane.Rob Murray, one of the flight instructors, said the passenger had never flown a plane before and had done a “remarkable job” given the circumstances.“It's a fantastic feeling, knowing I have achieved something and probably saved somebody's life,” Murray said.The passenger was unhurt but the pilot later died, police said.