For a soft-spoken, gentlemanly academic, John A. Pople sure had a way of causing a public stir.

Brett Coomer/Associated Press
John Pople when he won the Nobel prize in 1998.

His decision to leave his native England to join the Carnegie Institute of Technology and Mellon Institute in 1964 generated headlines and caused a political uproar in the British Parliament over the "brain drain" of British scientists headed for the United States.

And his work with early computers in the dingy basement of the Mellon Institute building in Oakland yielded a revolutionary set of computer codes that are still widely used by chemists, astrophysicists and other scientists around the globe.

For that work, Dr. Pople shared the 1998 Nobel Prize for chemistry. It also won him Israel's 1992 Wolf Prize in chemistry and a knighthood from Queen Elizabeth in 2003.

Dr. Pople, who retired from Carnegie Mellon University in 1991 and was a professor at Northwestern University, died Monday of colon cancer at the Chicago home of his daughter, Hilary Pople. He was 78.

"It's a great loss," said Hyung Kim, chemistry chairman at Carnegie Mellon. "There's no doubt about it."

Dr. Pople served on the chemistry faculty at Carnegie Mellon and Northwestern but considered himself a mathematician. The son of a clothier in Burnham-on-Sea, Somerset, in western England, he developed his interest in mathematics at age 12, reading ahead of the class to the end of his algebra textbook. He subsequently retrieved a calculus text from the trash and read it front to back.

He earned his doctorate in mathematics at Cambridge University in 1951. His involvement in chemistry began when he was looking for a research topic for his thesis, opting to study the structure of liquid water.

He taught at Cambridge before becoming superintendent of the basic physics division of the National Physics Laboratory in Teddington. But he was never able to obtain a faculty appointment in England and, after spending a sabbatical leave at Carnegie Tech in 1961-62, decided to move to Pittsburgh.

As it happened, his decision came as two other British scientists also were leaving for the United States. Concern about this brain drain caused the opposition party in Parliament to seek a "no confidence" vote against Prime Minister Harold Macmillan. As a government employee at the Teddington lab, Dr. Pople was not permitted to comment, leading one newspaper to headline: "Government Chemist Leaving and Won't Say Why."

"Scientific research receives much better backing in the United States and the scientists themselves get paid more," Dr. Pople explained to the Post-Gazette upon his arrival. He estimated as many as 10 percent of British scientists with doctorates were leaving because of low pay and lack of opportunity.

"John's presence was much sought after and much appreciated once he was here," recalled Guy Berry, a Carnegie Mellon chemistry professor who then worked at Mellon Institute. In those days, before the 1967 merger with Carnegie Tech, Mellon Institute officials saw him as key recruit as they tried to expand the institute's reputation beyond applied research to include a vigorous basic science program.

For his part, Dr. Pople, almost 40 and with a wife and four children, yearned not only for his faculty appointment at Carnegie Tech, but for the opportunity to work with Mellon's then-cutting-edge computers.

He focused on finding a way to use computers to calculate the electronic and structural properties of molecules, helping chemists develop new drugs or synthesize new polymers and aiding astrophysicists in analyzing exotic molecules seen in space.

These calculations involve quantum mechanics, the often bizarre physical rules that apply at atomic scales. The theories themselves had been around since the early 1900s, Kim noted, but solving the complex equations is beyond what is practical using paper and pencil.

Dr. Pople developed Gaussian, a software program that would perform these calculations. Because of the limitations in computing power during the 1960s and early '70s, he was forced to make it extremely efficient. Today, it can be run easily on desktop computers.

"He made this approach so popular that not only theoretical, but experimental chemists adopted it," said Kim, a theoretical and computational chemist. "It's used almost universally today."

Dr. Pople distributed his codes free of charge in the 1970s and early '80s. Some of his students later went into business selling Gaussian.

The Pople family lived in Churchill, but after the children grew up, Dr. Pople and his wife, Joy, set up house outside of Chicago in 1981 to be near their daughter. He took a position at Northwestern, but continued to operate a research group in Pittsburgh until 1993.

Dr. Pople shared the Nobel with Walter Kohn, a physicist at the University of California at Santa Barbara, though the two men had never collaborated. Kohn taught at Carnegie Tech during the 1950s.

In addition to his daughter, Dr. Pople is survived by three sons, Andrew, of Mt. Lebanon; Mark, of Missouri City, Tex., and Adrian of Cork, Ireland. A memorial service is planned March 29 in Evanston, Ill.