(March 8, 1879 – July 28, 1968)
Inspired by Enrico Fermi’s previous works on neutrons, Otto Hahn pioneered nuclear fission experiments. He was assisted by Fritz Strassmann; and the mechanism was explained by Lise Meitner and Otto Frisch. It was based on the assumption that splitting an atom of an element produces two atoms of smaller different elements. So, after firing neutrons at uranium, they observed that a lighter element (barium) was produced. And based on Niels Bohr’s ‘Droplet’ Model of the Nucleus, they inferred that the atom had split into lighter atoms: emitting neutrons and large amounts of energy. Frisch termed the process “nuclear fission”. Hahn was credited with the discovery; and is fondly called the “Father of Nuclear Chemistry”. Nuclear fission is not just a huge energy generator, it remains vital in health, agriculture and water managements. Hahn was a diligent researcher who dwelt on practicalities. He collaborated with prominent scientists of the 20th century, such as Ernest Rutherford and William Ramsay; and corresponded with others like James Chadwick and Albert Einstein. Like his compatriot, David Hilbert, Otto Hahn was distraught by Adolf Hitler’s racist policies which oversaw an unprecedented holocaust between the 1930s and 40s. After the Second World War, a grateful Albert Einstein praised him for opposing the Nazis. In view of that, Elizabeth Rona opined that he deserved a Nobel Peace Prize. Otto Hahn also discovered the nuclear isomerism, radioactive recoil, several elements, and collaborated in the Quantitative Analysis which led to the so-called Fajans-Paneth-Hahn Law of Precipitation and Adsorption.