The world of physics was turned upside down at the start of the 20th Century by Albert Einstein. He published his theory of special relativity in his 1905 paper and with it introduced the notion of quanta. But even though this paper dealt with the particle nature of light, it didn’t call the particles photons. That came a couple of decades later and from an American physical chemist called Gilbert Newton Lewis.
Born in Weymouth Landing, Massachusetts, in 1875, Lewis started reading at the age of three. Even though he briefly attended public schools from the age of nine to 14, the bulk of his education happened at home by tutors. He enrolled at the University of Nebraska and transferred to Harvard University three years later at the age of 17.
PhD at 24!
Having completed his Bachelor of Science degree in 1896, Lewis turned his attention to a PhD, and finished it in 1899, at the young age of 24. He spent a year as a travelling fellow in Germany, which allowed him to mingle with some of the best minds in physical chemistry, before returning to Harvard as an instructor in electro-chemistry and thermodynamics.
In 1904, Lewis moved to the Philippines and spent a year with the Bureau of Weights and Measures at Manila. He took a faculty position at the Massachusetts Institute of Technology before becoming a Professor and Dean at the University of California at Berkeley, where he spent much of his scientific career. His teaching career involved mentoring nearly 300 PhD candidates. In fact, 20 of his students went on to become Nobel Prize winners.
The Atom and the Molecule
Despite starting out with thermodynamics and then working with the nascent theory of relativity, Lewis’ best work was on chemical bonding. His 1916 paper “The Atom and the Molecule” talks about the notion of the covalent bond and is considered a classic. He outlined the electron-pair theory of acid-base reactions in a 1923 paper.
It is interesting to note that as early as 1902, Lewis used rough sketches in his lecture notes, denoting cube-shaped atoms with electrons possibly occupying the corners.
He eventually realised that electrons in an atom pair up around the nucleus and that these paired electrons could be shared by two bonding atoms – ideas that influenced future work in the subject.
In a December 18, 1926 letter to the journal Nature, Lewis coined the word “photon”, which now describes a particle representing a quantum of electromagnetic radiation. He proposed the term as a carrier of radiant energy and not as a particle of light. Even though his concept was quickly forgotten, the name stayed on.
Soon, photons turned out to be an able substitute to refer to what Einstein originally termed “light quantum” (lichtquant) in his 1905 paper. By the mid-1930s, photon became the preferred term for referring to Einstein’s light quantum.
Never won the Nobel
Despite his many scientific accomplishments and honours, Lewis never won the Nobel Prize. He was nominated for the Nobel Prize in chemistry 41 times, and even though many scientists still believe he well deserved it, he never got around to winning it.
To make matters worst, Lewis had a tragic end in 1946. Having inhaled the toxic fumes of liquid hydrogen cyanide, he was found dead under a workbench in his laboratory by one of his graduate students.
Lewis had been working with the substance, but a leakage had caused it to spread through his workspace. Even though the cause of death was declared as coronary artery disease and there was no sign of cyanosis, rumours persist till this day that Lewis, who had been battling depression, committed suicide.
