George S. Hammond was a chemist

Chemist

A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...

 at Iowa State University

Iowa State University

Iowa State University of Science and Technology, more commonly known as Iowa State University , is a public land-grant and space-grant research university located in Ames, Iowa, United States. Iowa State has produced astronauts, scientists, and Nobel and Pulitzer Prize winners, along with a host of...

 and the California Institute of Technology

California Institute of Technology

The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...

. Among his awards were the Norris Award in 1968 and the Priestley Medal

Priestley Medal

The Priestley Medal is the highest honor conferred by the American Chemical Society and is awarded for distinguished service in the field of chemistry. Established in 1922, the award is named after Joseph Priestley, the discoverer of oxygen who immigrated to the United States of America in 1794...

 in 1976 and the National Medal of Science in 1994. Hammond's postulate

Hammond's Postulate

Hammond's postulate, also referred to as the Hammond–Leffler postulate, is a hypothesis, derived from transition state theory, concerning the transition state of organic chemical reactions, which states that:-Interpreting the postulate:...

, also known as the Hammond-Leffler postulate, was based on his 1955 publication.

Hammond was a leader in the field of photochemistry and was widely credited with creating the discipline of organic photochemistry.