John Light, pioneer in theoretical chemical dynamics, 1934-2016

Prof. Emeritus John Light, one of the first scientists to describe the dynamics of chemical reactions on a molecular scale and longtime editor of the Journal of Chemical Physics, died Jan. 18, in a Denver hospital following a severe illness. He was 81.

“John was a wonderful friend and colleague,” said Donald Levy, UChicago’s vice president for research and for national laboratories and the Albert A. Michelson Distinguished Service Professor in Chemistry. “Getting to work with him, both at the Journal of Chemical Physics and as a scientific colleague, was a major factor in making a career in our department so enjoyable and productive. The physical chemistry group was outstanding by any measure, and John was one of the leaders in making it so.”

Gregory Voth, the Haig P. Papazian Distinguished Service Professor in Chemistry, praised Light as “a wonderful man and a great theorist. His long editorship of the Journal of Chemical Physics, in many ways, oversaw a golden era in the field of chemical physics,” said Voth.

James Norris Jr. also had fond memories of Light, whom he called “a true champion of the department and the University.” Norris, the Robert A. Millikan Distinguished Service Professor Emeritus in Chemistry, recalled visiting often during Light’s tenure as editor of the Journal of Chemical Physics. “He was always willing to take time from his busy editorial duties when I sought advice on scientific or departmental topics,” Norris said.

Light rose to prominence in theoretical chemical dynamics in the 1960s. Before then, scientists relied on macroscopic-scale experiments, such as pouring one type of fluid into another, to study how chemicals would react with each other. But then physical chemists began colliding molecular beams of reactants under vacuum conditions and examining the angles at which product molecules were found, in order to measure the probability that a chemical reaction takes place.

These molecular beam experiments inspired Light to understand chemical dynamics at a molecular scale. “Young people are always looking for something new to do, and this was something new,” said William H. Miller, the Kenneth S. Pitzer Distinguished Professor Emeritus in Chemistry at the University of California, Berkeley. “Inspired by these molecular beam experiments, John was one of the real pioneers in developing the theory of chemical dynamics starting in the 1960s,” Miller said.

Light had reached the pinnacle of the field in the late 1960s, just when Miller was starting out. Miller told himself that “if I could follow his pathway, that would really be an accomplishment. He was one of my early heroes.”

Light’s development of theoretical and computational methods for determining reaction rates and related information are important for modeling combustion and atmospheric chemistry, noted George C. Schatz, the Morrison Professor of Chemistry at Northwestern University and editor-in-chief of the Journal of Physical Chemistry.

“John was expert at developing numerical tools and algorithms,” Schatz said. “Many methods that came out of his research work are still in common use decades later.”

Schatz also credited Light with teaching him much about how to be a journal editor.

“He had a sense of professionalism that I very much admired,” Schatz said. “This did much to secure the reputation of the journal, making it the top journal for the fields that it represented while he was editor. Thanks to John, the University of Chicago was the top institution in the field of chemical physics during his period as editor.”

John C. Light was born Nov. 24, 1934, in Mount Vernon, N.Y. He received his bachelor’s degree with honors from Oberlin College in 1956, and his PhD from Harvard University in 1960. From 1959 to 1961 he was a National Science Foundation postdoctoral fellow at Université Libre de Bruxelles in Belgium. Light became an instructor in UChicago’s Department of Chemistry and the James Franck Institute in 1961. By 1970 he had earned the rank of professor.

Light also held appointments as a visiting professor at Yale University in 1968; as a research associate at Argonne National Laboratory from 1975 to 1980; and as a visiting scientist at JILA, a joint institute of the University of Colorado, Boulder, and the National Institute of Standards and Technology, in 1976-77. He consulted for the Institute for Defense Analyses, IBM Research Laboratories and Lawrence Livermore Laboratory.

Administratively, Light served as director of UChicago’s Materials Research Laboratory from 1970 to 1973, and as chair of the chemistry department from 1980 to 1982. As a research mentor, he oversaw the work of 31 graduate students and 25 postdoctoral fellows. Many of them are actively conducting research at universities worldwide. Light praised their contributions in a special issue of the Journal of Physical Chemistry A that was published in his honor in 2006.

“I learned much more from them than they did from me,” wrote Light, who retired as professor emeritus in 2001. “It has been a great pleasure to have worked with so many gifted people.”

Although Light retired as professor emeritus in 2001, he continued to attend the occasional scientific meeting. “He was very good at digging into the essentials of research topics, so we valued his presence,” said Schatz. “He will be greatly missed.”

In 2004, Light and his wife retired to Colorado’s Arkansas River Valley, to the town of Nathrop, Colo. There he enjoyed the community, skiing, hiking, horseback riding and their dog, Libby.

Light was a fellow of the Alfred P. Sloan Foundation, the American Physical Society and the American Association for the Advancement of Science. He also was an elected member of the International Academy of Quantum Molecular Science; a member of Sigma Xi, the international honor society of science and engineering; and of the Phi Beta Kappa academic honor society

Light is survived by his wife, Phyllis Kittel, whom he married in UChicago’s Bond Chapel; a brother, Richard Light of New York; three sons by his first wife, the late Nancy Seaburg Light: David (and Rose) Light of Chicago; Robert (and Alison) Light of Boston; and Erik (and Jenny) Light of Washington, D.C.; 10 grandchildren: Isabella, Ethan, Bryce, Michael and Clara Light of Chicago; Alex, Hazel and Ian Light of Boston; and Christine and Jennifer Light of Washington, D.C.

The family will hold memorial services near the home in Colorado and at the Light family estate in Austerlitz, N.Y. Arrangements for a memorial service and symposium on the University campus are pending.