Clinton Davisson | Biography

A major focus of Clinton Davisson's research at Bell Telephone Laboratories (formerly Western Electric Company) was the scattering of electrons by crystals . In 1927, while working with a colleague named Lester Germer, Davisson accidentally discovered evidence to support the earlier hypothesis of Prince Louis Victor de Broglie that a beam of electrons has wave properties. For this discovery, Davisson was awarded a share of the 1937 Nobel Prize in physics. He remained at Bell until his retirement in 1946.

Clinton Joseph Davisson was born in Bloomington, Illinois, on October 22, 1881. His father, Joseph Davisson, was a veteran of the Union Army who worked as a contract painter; his mother was the former Mary Calvert, a schoolteacher before her marriage. The Davissons also had one daughter, Carrie. Young Clinton attended local schools and graduated from Bloomington High School in 1902. He entered the University of Chicago on a scholarship, as a physics major.

Davisson's intellectual promise soon became apparent. At the end of his sophomore year, one of his professors, Nobel laureate Robert A. Millikan , recommended Davisson as a replacement for a physics instructor at nearby Purdue University who had recently died. Davisson took that post and spent the last half of the 1903-04 academic year at Purdue. He returned to Chicago in the fall of 1904, but was there only a year when he was offered a position as instructor in physics at Princeton University the following autumn. At Princeton he also worked as a research assistant under another Nobel winner, Owen W. Richardson . Over the next six years, Davisson worked on both his B.S. at Chicago by attending summer sessions and his Ph.D. at Princeton during the regular academic year. He received the former in 1908 and the latter in 1911.

Shortly after graduation from Princeton, on August 4, 1911, Davisson was married to the former Charlotte Sara Richardson, his mentor's sister. Davisson had met Richardson while she was staying with her brother at Princeton on a visit from England. The Davissons had four children, Clinton Owen Calvert, James Willans, Richard Joseph, and Elizabeth Mary. A few weeks after his marriage, Davisson began his new job as assistant professor of physics at Carnegie Institute of Technology in Pittsburgh.

Davisson's experience at Carnegie over the next six years was largely unsatisfactory. His teaching load was so heavy that he had virtually no time to spend on research. Indeed, as Mervin J. Kelly writes in his obituary of Davisson in the National Academy of Sciences' Biographical Memoirs, "he had been able to carry only one research to the point where, with his lifelong high standards, he would publish it." As a result, Davisson was not at all disappointed in May 1917 to receive a leave of absence from Carnegie to take on war-related research in the Engineering Department of the Western Electric Company (later, the Bell Telephone Laboratories). When the war ended, Davisson chose to continue on at Western Electric rather than to return to academic life. He remained with the company for another 29 years, retiring in 1946 at the age of 65.

Laboratory Accident Leads to Discovery of Electron Diffraction

Davisson's first research assignment at Western Electric was carried out in connection with a patent suit in which the company was involved regarding rights on vacuum tubes. That research concerned a study of electron emission patterns produced when a metal filament is bombarded by positive ions. When that research was completed, Davisson moved on to a variation of that topic, the characteristics of electron emission when metals are bombarded by electrons rather than by positive ions. For about six years, Davisson and a colleague, C. H. Kunsman, bombarded a variety of metals with electrons and measured the angles at which secondary electrons were emitted from the metal surface. Throughout this period, however, they were unable to develop a theoretical model that explained their results.

Finally, in April 1925, a laboratory accident provided some key new information. A vacuum tube being used by Davisson and Lester Germer (who had replaced Kunsman) exploded, resulting in the rapid oxidation of the nickel target inside the tube. Intending to restore the target for re-use in another vacuum tube, Davisson was forced to re-heat the nickel for an extended period of time. When new experiments were begun using vacuum tubes containing the rejuvenated nickel target, some remarkable results were obtained. Specifically, electrons were not just reflected from the nickel target, but diffracted as well. Later studies revealed that the heating process had converted many tiny nickel crystals in the original sample to a few much larger crystals in the restored sample.

The new findings were significant because diffraction is a characteristic of waves. Although the Davisson-Germer results suggested that electron beams reflected from the nickel target behaved as if they were traveling in waves, Davisson did not fully appreciate the meaning of his results until the summer of 1926. While attending a meeting of the British Association for the Advancement of Science, he learned for the first time about Prince Louis de Broglie's recently announced hypothesis of the wave nature of electrons. Using de Broglie's theory, Davisson was able to calculate the wavelength of the electrons diffracted in his experiment. His results matched de Broglie's predictions so closely that they could be regarded as confirmation of the French physicist's theory.

Davisson continued his research on electron scattering over the next two decades of his tenure, first at Western Electric, and then at Bell Laboratories. After his retirement in 1946 he accepted an appointment as visiting professor of physics at the University of Virginia. He resigned from that post in 1954 and died in Charlottesville, Virginia, on February 1, 1958. In addition to the 1937 Nobel Prize, Davisson received a number of other honors and awards, including the Comstock Prize of the National Academy of Sciences in 1928, the Elliot Cresson Medal of the Franklin Institute in 1935, the Hughes Medal of the Royal Society in 1935, and the University of Chicago Alumni Medal in 1941.