Carbon-14 Carbon-14 Carbon-14, (C), or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples. Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California. Its existence had been suggested by Franz Kurie in 1934. There are three naturally occurring isotopes of carbon on Earth: carbon-12, which makes up 99% of all carbon on
Kinetic isotope effect effects to be easily measured and interpreted. In contrast, secondary effects are generally very small for heavier elements and close in magnitude to the experimental uncertainty, which complicates their interpretation and limits their utility. In the context of isotope effects, "hydrogen" is frequently used to refer to the light isotope, protium (H), specifically. In the rest of this article, reference to "hydrogen" and "deuterium" in parallel grammatical constructions or direct comparisons between them should be interpreted as referring to protium and deuterium. The theory of kinetic isotope effects was first formulated by Jacob Bigeleisen in 1949. Bigeleisen's general formula for