The heritage collection of Peter Debye

by Jurrie Reiding and Ernst Homburg

The University Library Maastricht holds a private collection of books from the Maastricht scientist Peter Debye (1884-1966). Debye received the 1936 Nobel Prize in Chemistry. Thanks to Debye’s heirs, the books ended up in City Library of Maastricht in the late1960s, which in 1996 handed them over to the University Library. Recently a typical example of a ‘miscellaneous item’ showed up in the archives of Maastricht University: a long play record with a recording from 1962, when Debye was briefly back in Maastricht from the United States in order to attend the Hustinx prizes ceremony. It is quite special to hear the voice of this internationally known Maastricht native via the You Tube channel of Maastricht https://www.youtube.com/watch?v=G8KY-r598XI

On the afternoon of Saturday 4 August, 1962, the Maastricht Municipal Theatre was packed. Debye was not just back in his former hometown to present the Hustinx prizes, but also to deliver a lecture. As remembered by Evert Verwey, director of the Philips Physics Laboratory: ‘This lecture by Debye was the strangest one I ever heard him deliver. Debye was standing near the edge of the stage, where in his familiar, rather high-pitched voice, he grabbed the opportunity to tell his story right in front of a mixed audience – it was more than a unique experience. This was Debye all over, as he was standing there having been unable to refuse yet another invitation because this was Maastricht, and also because he wanted to share with others the science that was his life and everything’. The lecture was entitled ‘The Measurement of Molecules.’ Several decades before, Time Magazine already called him ‘The Master of the Molecule’. Verwey made sure that this title was used when Debye’s lecture was later issued on a long play record.

Peter Debye was born on 24 March 1884 in a house on the Maastrichter Smedenstraat in Maastricht in a middleclass family. His father was a blacksmith. In 1901, after primary school and graduating from the municipal college, he moved to Aachen, across the border in Germany, to study electrical engineering at the Rheinisch-Westfälische Technische Hochschule (RWTH).

Debye’s scientific breakthrough came in 1912, when at 28 he published an article on specific heat of solids. As of 1875 it was known that the specific heat decreased at declining temperatures, but scientists failed to understand this effect. Debye introduced a completely new model: elastic waves as transporters of heat. This mathematical model was used to explain the decrease through quantum effects, and this further provided support to the 1900 quantum theory of Max Planck. Colleagues called Debye’s approach daring, if not reckless, yet at the same time brilliant. His article still serves as a foundation of modern solid state physics. A few years later Albert Einstein would write: ‘We only have one Debye, and his life span is shorter than infinite’.
           

In 1912 Debye solved a second ‘cold case’ in physics. For decades scientists failed to understand why substances such as water and alcohol have such high dielectric constants – why they are so responsive to electrical fields. Debye posited that most molecules have a permanent dipole, apart from the induced dipole which has to be externally generated. Under the motto ‘success ensures truth’, he convinced the world of the existence of permanent dipoles. After the book publication of his theory, in 1929, international students would flock to Debye’s laboratory in Leipzig, while scientists began to measure dipole moments of molecules in laboratories across the world.
           

Debye also solved a third cold case. According to the old theory of Svante Arrhenius, electrolytes (salts, acids and bases) were divided into weak and strong. Strong electrolytes, however, which were believed to split up fully into ions in a solution, behaved as weak in several experiments. In an ingenious way, Debye explained this anomaly in 1923: in a solution, positive ions surround themselves with slightly more negative ions than positive ones, while the opposite applies for negative ions. This once again meant work for hundreds of laboratories across the world.
           

These are just several highlights from Debye’s extensive track record. A guiding element in his work was the interaction of electromagnetic radiation (light, X-ray) and matter. He was awarded the 1936 Nobel Prize in Chemistry for his work on dipoles and his X-ray study of molecules in the gas phase. When in 1940 he moved to the US, he was often asked: are you a physicist or a chemist? In fact, he was both. And was he a theoretician or rather an experimentalist? Again, he was both. Debye’s strength precisely was that he took a multidisciplinary approach, before this became a fashionable term, based on a solid mathematical toolkit. In this way he could be a pioneer, performing path-breaking work for others. He was his own man, as the British say, as a scientist as well as a citizen – one who did not bother with rank or status.

In 1946 Debye became an American citizen. In contrast to the European period of his life, when he regularly moved, he stayed put for the remainder of his career at Cornell University. After his retirement in 1952 he continued to conduct research, in particular on plastics and polymers. In April 1966 he suffered a heart attack, followed by a second and fatal one in November of that same year. He died at age 82 and was buried in Ithaca, New York.           

In 2006 Debye’s reputation received an unexpected blow. In a book on Einstein, a Dutch science journalist accused Debye of Nazi collaboration, when in the 1930s he served as chairman of the society of German physicists. Within a matter of weeks, in a panicked response, the universities of Utrecht and Maastricht removed the name of Debye, as linked to a scientific institute and a scientific award, respectively. This prompted the Dutch government to commission a report from the Netherlands Institute for War Documentation (NIOD). This report was subsequently evaluated by a special committee led by former politician Jan Terlouw. It arrived at the conclusion that Debye did not engage in collaboration. In other words, the ‘Debye affair’ proved to be a storm in a teacup. The committee recommended Debye’s rehabilitation. If Utrecht University did follow up on this recommendation, Maastricht University did not.

Illustrations: from left to right and from top to bottom:

Debye in 1920 - F. Schmelhaus Wikimedia Commons

Debye in 1936 - Nobel Foundation

Debye in 1950 - Wikimedia Commons

Debye on stamp 1995 - Wikimedia Commons

Cover boek Debye - University Library Maastricht

Cover boek Debye - University Library Maastricht