Peter Georg Debrunner (1931–2024): Pioneer in the Application of Mössbauer Spectroscopy in Biological Physics

Peter Debrunner was one of the emigrants from Europe, in his case Switzerland, who injected vitality and excitement into the Physics Department of the University of Illinois at Urbana–Champaign (UIUC). Peter received his Ph.D. at ETH (Eidgenössische Technische Hochschule) in Zürich and accepted a postdoctoral position in 1960 with Hans Frauenfelder, another Swiss emigrant. During his 40-year career at the UIUC, he achieved the rank of Professor of Physics, with research focused on electron paramagnetic resonance and the Mössbauer effect as applied to heme proteins. Peter was a bright, unassuming physicist with a balanced perspective and was admired and respected by his colleagues for his solid grasp of physics and pioneering work in biological physics, a new field in 1960. We have included here reminiscences/ tributes by several who had worked with him: Robert Austin; Paul Champion; Adam Gilmore; John D. Lipscomb; Eckard Münck.; J. Timothy Sage; Charles Schulz; and Stephen (Steve) Sligar.