Professor Emeritus Richard Warren Fessenden died on Tuesday, February 11, 2020

Author: Laura Mortlock-McMinn

It is with sadness that the NDRL learned of this loss. Dick came to us from the Bushy Run Lab at Carnegie-Mellon University with Bob Schuler in 1976. He continued to make fundamental and significant advances in magnetic resonance and dielectric loss spectroscopies till his retirement in 1999, remaining scientifically active here for another ten years. During his time with us he touched the lives of many colleagues, staff and graduate students.

He graduated with a BS in physical chemistry from U Mass in 1955, moving on to MIT to do graduate work with John Waugh and obtaining a PhD, again in the same discipline, in 1958 with the support of a National Science Foundation (NSF) fellowship. Before continuing with his doctoral studies he spent time at the Brookhaven National Laboratory with Bob Schuler, an interaction which would pivotally shape his future career.

Again with the support of the NSF, he moved to Caltech for a postdoctoral stay with Harden McConnell. Then in 1959 he rejoined Bob as a Fellow in the Radiation Research Labs of the Mellon Institute, being promoted to Senior status in 1962. The pair's 1963 magnum opus on electron spin resonance (ESR) in alkyl radicals remains the longest original research article published in the Journal of Chemical Physics to date and with almost 2,000 citations.

With the incorporation of Radiation Research Lab at Bushy Run as part of Carnegie-Mellon University, he was named a Professor of Chemistry in 1967 on the basis of his significant research discoveries.

These included the initial observation of the chemically induced dynamic spin polarization phenomenon, first reported in 1962, though a complete explanation had to wait several years. Dick was very much a builder of scientific equipment and early successes such as this hinged on his development of a time-resolved ESR technique. He was also the first to identify second-order splittings as the source of additional structure observed in his extremely well-resolved spectra. A very careful and thorough worker, Dick was never ready to publish until he fully understood the observations he had made.

The consolidation of the radiation chemistry effort in the Bushy Run Lab at the Carnegie-Mellon with the Notre Dame program in 1976, brought Dick here as Professor in the Department of Chemistry and Radiation Laboratory. He served as Associate Director of the NDRL from 78-94, being responsible for the addition of much new equipment and the development of novel experimental capabilities.

The time-resolved ESR technique flourished at the NDRL allowing the confident explanation of a number of unusual phenomena in even simple radicals. Other applications of microwave radiation were also explored, including the reliable determination of dipole moments in photoexcited states, then an area of some controversy.

In 1998 he was presented with the Silver Medal of the International ESR/EPR Society in honor of his fundamental contributions towards ESR spectroscopy.

Upon his retirement in 1999, Dick became Professor Emeritus, though he maintained a keen interest in the fate of his many unique experimental apparatuses and willingly offered assistance and guidance to those now using them.

In 2012 Dick received the prestigious Zavoisky award for lifetime achievement in the field, a fitting tribute to his scientific accomplishments, with more than 150 publications, garnering almost 12,000 citations.