George William Series, 22 February 1920 - 2 January 1995

George William Series was an optical spectroscopist who devoted his early research at the Clarendon Laboratory, Oxford, to simple atoms such as hydrogen and ionized helium. These were testing grounds for new advances in both experiment and theory, particularly that of the ‘Lamb shift’. Radiofrequency measurements at Columbia University, New York, had begun immediately after the end of World War II. The team led by Isaac Isidore Rabi showed that both the fine structure and the hyperfine structure of the hydrogen atom were at variance with previous results. Modifications were needed to a theory whose bases were thought to have been well established from the first days of quantum mechanics, and quantum electrodynamics was born. After radiofrequency spectroscopy had shown that experimental physics could still show such surprises, George Series realized that optical spectroscopy should be applied to these problems. With great experimental skill, he measured the fine and hyperfine splittings of hydrogen, deuterium and ions of the light isotope of helium of atomic mass 3. He followed this with the application of optical/radiofrequency double resonance to excited states of atoms, and many other novel techniques. At Oxford, these provided exciting results, and were combined with detailed theory. Later, as Professor at Reading University from 1968 to 1982, he continued with the application of tuneable lasers to new types of optical experiments.