A-Bomb Pioneer Hirschfelder Dies

Joseph O. Hirschfelder, a founder of modern theoretical chemistry and a key participant in the Manhattan Project during World War II, has died of cancer.

Hirschfelder, a University of Wisconsin professor emeritus of chemistry, was 78 when he died Friday at his home.

He was a key player in the creation of the atomic bomb built in Los Alamos, N.M., that was used against Japan, and was the first to predict the existence of radioactive fallout, the university said.

Hirschfelder was best known as the co-author of the work “The Molecular Theory of Gases and Liquids,” and also made contributions toward a fundamental understanding of flames and detonation.

In 1976, he was given the National Medal of Science, the nation’s highest scientific achievement award.

Hirschfelder joined the chemistry faculty at Wisconsin in 1937 and--except for a leave of absence during World War II to work at the Los Alamos weapons laboratory--spent his career there.