Ronald L. Cappelletti

Ronald L. Cappelletti, a spirit of curiosity, inquiry, and discovery, passed away on 6 July 2024. He is survived by siblings and four children.

Ron was born in Waterbury, Connecticut, in 1940. He graduated valedictorian from Fairfield University in 1962 with a degree in physics and mathematics. In 1966, he received a PhD at the University of Illinois under Donald Ginsburg, studying the far-IR superconducting energy gap in niobium alloys.

After a postdoctoral stint at Iowa State University with Douglas Finnemore, Ron joined the faculty of Ohio University in 1968. There, he initiated the undergraduate Physics Honors Tutorial program with David Onley, was an architect and first director of the university-wide Condensed Matter and Surface Sciences program, and was mentor to 12 PhD students.

Ron was a gifted experimentalist who elucidated Michael Thorpe’s predicted floppy-to-rigid transition in Ge–Se glasses. He was a pioneer of the dynamics of solid C₆₀, probed by inelastic neutron scattering. He moved to NIST in 1999 and continued research on amorphous materials, disordered and glassy carbons, and neutron interferometry until his retirement in 2014.

Ron was a lifelong musician and an avid student and promoter of Italian culture, history, and language. He was president emeritus of the Italian Cultural Society of Washington, DC. He radiated a contagious curiosity and enthusiasm for deeper understanding across his vast range of interests. Ron was a beloved friend, colleague, and mentor. We felt our lives brightened by his friendship.

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