Hans Frauenfelder

Hans Frauenfelder (July 28, 1922 – July 10, 2022) was an American physicist and biophysicist notable for his discovery of perturbed angular correlation (PAC) in 1951. In the modern day, PAC spectroscopy is widely used in the study of condensed matter physics. Within biophysics, he is known for his experimental and theoretical research on the dynamical behavior of protein tertiary structure. Provided by Wikipedia