Marilyn E. Jacox, an internationally recognized leader in molecular spectroscopy, died on Oct. 30, 2013 at the age of 84 after suffering complications from a bout with pneumonia following a holiday expedition to Alaska. She spent nearly her entire career at the National Bureau of Standards (NBS) and the National Institute of Standards and Technology (NIST) in Gaithersburg MD. Her decades of distinguished research culminated in comprehensive spectral databases as well as a variety of widely cited scientific publications, more than 200 in all.
A physical chemist, NIST fellow, and active scientist emeritus at the time of her death, Jacox specialized in the infrared spectroscopy of free radicals, small molecular ions, and other reaction intermediates, typically embedded in a surrounding matrix of inert species such as nitrogen or noble gases at cryogenic temperatures. Her "matrix isolation" measurements reveal otherwise hidden properties of the carriers of many chemical reactions and have found applications in quantum chemistry, chemical kinetics, atmospheric chemistry, and combustion chemistry.
"The infrared spectrum of a molecule tells us how its atoms vibrate with respect to one another. Analysis of this spectrum provides sometimes surprising information about the structure and chemical bonding of the molecule," she wrote in 2010 describing her work. Thousands of measurements make up her compilation of Vibrational and Electronic Energy Levels of Polyatomic Transient Molecules (1990) and are part of NIST's online library of standard reference data.
"Marilyn was a scientific hero to many of us," said Gerald Fraser, Chief of NIST's Sensor Science Division, "both for her important and lasting contributions, and as an ardent supporter of women and young people in science."
Jacox became interested in physical chemistry in high school, and pursued it as an undergraduate at Utica College, during her doctoral research at Cornell University and postdoctoral experience at the University of North Carolina, and in her appointment in 1958 as a Fellow of the Mellon Institute of Industrial Research in Pittsburgh. In 1962, she joined NBS/NIST, where she and longtime collaborator Dolphus Milligan made pioneering spectral measurements that spanned decades.
"No one in the matrix isolation community will disagree that she is the most important contributor after George Pimentel initiated the matrix isolation technique in 1954. She conducted numerous ground-breaking studies, and her careful work was seldom questioned," said Yuan-Pern Lee, a colleague at Taiwan's Institute of Atomic and Molecular Sciences, Academia Sinica. "She also wrote many reviews and book chapters to summarize important advances in this field. When the George Pimentel Prize for Advances in Matrix Isolation was initiated in 2005, naturally she was the first to receive it."
Her many other awards include the U.S. Department of Commerce Gold Medal for Distinguished Service, the E. Bright Wilson Award in Spectroscopy from the American Chemical Society, the Federal Woman's Award, the NIST Samuel Wesley Stratton Award, and the Washington Academy of Sciences Award for Distinguished Career in Science. She was a Fellow of the American Physical Society, the American Association for the Advancement of Science, and the Washington Academy of Sciences. She served on the editorial boards of two major journals, and in 2000 was honored by a Festschrift in the Journal of Physical Chemistry.
Lester Andrews, Professor Emeritus of Chemistry at the University of Virginia, a friend and colleague for many years. said, "As a scientist, Marilyn was fiercely competitive, as we all must be, but she was objective and honest in all of her dealings. I only wish that she could have refereed all of my submitted manuscripts. I would have gained more improvements for my papers than I could have from any other person."
Molecular physicist William R. M. Graham, Chair of the Department of Physics and Astronomy at Texas Christian University, said that Jacox's "exacting standards in her research and its publication set a very high bar for her colleagues in the field." In addition, "with her warm personality she generously shared results and advice with her colleagues, particularly young people setting out on their careers. She was a strong advocate for women in science, and her career provided an inspiring example."
Always exceptionally busy, Marilyn still found time for interests other than science. She was passionate about piano, photography, and exploratory travel. Visitors to her home were often treated to a slide show reminiscent of a National Geographic exhibition. Marilyn was a member of Bradley Hills Presbyterian Church in Bethesda MD for 25 years where she served as an Elder and was very active in adult education and a supporter of numerous worthy causes.
