How did Manfred Eigen advance the study of fast chemical reactions?

Manfred Eigen revolutionized the study of extremely rapid chemical reactions by developing relaxation techniques in the 1950s.12

Prior to his work, measuring reactions that occurred in a fraction of a second was difficult because the time required to mix reactants often exceeded the reaction's half-life. Eigen overcame this by starting with a system already at equilibrium and applying a sudden, external stress—such as a rapid change in temperature—to briefly disrupt that state. As the system "relaxed" to reach a new equilibrium, Eigen used absorption spectroscopy to monitor the process in the extremely brief interval between the two states.21

The most prominent of these methods is the temperature-jump (T-jump) technique, which allows researchers to study the kinetics of fast processes by measuring the time it takes for the system to re-equilibrate. This approach provided critical insights into reaction mechanisms, such as hydrogen ion formation and keto-enol tautomerism, earning Eigen a share of the 1967 Nobel Prize for Chemistry.21