Technically, Marcus is an American citizen, but he began his major work while he was still Canadian. In 1949 he went to the US, and became a naturalized citizen there in 1958. Beginning in 1956, he wrote a series of papers over a nine-year period developing what is now called the Marcus theory of electron transfer reactions, which was later experimentally verified. Marcus theory explains such phenomena as photosynthesis, electrically conducting polymers, chemiluminescence and corrosion as well as many other chemical reactions. Marcus continued to win awards for his work all through the 1990s.

Sources: Physics Today, Jan 1993; Who’s Who in America 1994; Photo from Caltech website.