Was Nobelist Peter Debye a Nazi sympathizer or an Allied informer? Credit: Hulton Archive/Imagno/Getty Images

Peter Debye, the Dutch winner of the 1936 Nobel Prize in Chemistry whose reputation was sullied in 2006 by allegations that he was a Nazi sympathizer, could in fact have been an anti-Nazi informer to the Allies during the approach to the Second World War.

Jurrie Reiding, a retired chemist in the Netherlands, examined Debye's private correspondence and concluded that he might have supplied information to a spy working for the British intelligence agency MI6 in Berlin. The finding is published in Ambix1.

Reiding says that Debye was a friend of Paul Rosbaud, an Austrian working at the Kaiser Wilhelm Institute for Physics in Berlin, of which Debye was director between 1935 and 1939. Rosbaud, who loathed the Nazis, was recruited by MI6 to supply them with scientific information including details of the development of the V1 and V2 rockets and German attempts to develop an atomic bomb. He remained in Berlin throughout the war. Even now, information about Rosbaud's activities under the codename Griffin remain classified.

Debye maintained his friendship with Rosbaud, who clearly admired him, after the war, continuing to write to him until at least until three years before Debye's death in 1966. "The close friendship between Rosbaud and Debye makes it almost unquestionable that Debye was an anti-Nazi," says Reiding.

And he points out that Debye, as a prominent scientist in pre-war Nazi Germany, would have had access to highly sensitive information about war technology. "Therefore," says Reiding, "the hypothesis that Debye was a secret informant for Rosbaud does not appear too bold."

Dirty hands?

Much of the condemnation of Debye stemmed from his actions as president of the German Physical Society (DPG) in 1938. Because of a German law demanding the dismissal of all Jewish university professors, introduced in 1933 by Hitler's Nazi regime, the DPG felt compelled to expel its few remaining Jewish members. Debye sent a letter to members explaining this, citing "circumstances beyond our control" and signing off with "Heil Hitler!" But "under the circumstances of those days, it was almost impossible not to write such a letter", because anyone flouting the law would face reprisals, says Ernst Homburg, a science historian at the University of Maastricht in the Netherlands.

In January 2006, this letter was described in an article in Dutch magazine Vrij Nederland and in the book Einstein in Nederland (Ambo, 2006), both by Sybe Rispens, a science writer based in Berlin. Rispens claimed that this and other evidence points to Debye having colluded with the Nazis. The ensuing media controversy caused such alarm that the University of Utrecht in the Netherlands removed Debye's name from its institute for nanomaterials science, and the University of Maastricht withdrew its involvement from the annual Debye Prize for scientific research.

This caused a storm of protest from scientists. Critics pointed out, for example, that by accepting his Nobel Prize Debye risked the displeasure of the Nazis, who had forbidden all Germans from doing so. Debye helped the Jewish nuclear physicist Lise Meitner escape to Holland in 1938, and the Nazis opposed his chairmanship of the DPG because they considered him too friendly towards Jews. After Debye left Germany in 1940 to work at Cornell University in Ithaca, New York, he aided the Allied war effort enthusiastically, especially through his work on polymers and synthetic rubber.

Ambiguous times

The furore led the Dutch Ministry of Education to commission the Institute for War Documentation in Amsterdam to investigate the affair. Although its report in 2007 softened the accusations, the institute claimed that Debye had been guilty of "opportunism", and accused him of "keeping the back door open" once in the United States by secretly sustaining contacts with Nazi Germany.

Peter Morris, editor of Ambix and a historian of chemistry, says that "in the Netherlands and, to a lesser extent, the United States this affair severely damaged Debye's reputation".

Nonetheless, in 2008 a Dutch government committee advised the universities of Utrecht and Maastricht that the evidence of Debye's 'bad faith' was considered equivocal. The Debye Institute at Utrecht was reinstated, and the University of Maastricht is set to be award the Debye Prize again next year.

"There were already enough arguments for Debye's 'rehabilitation' before this article," says Homburg, who calls Rispens's 2006 book "heavily flawed". But he adds that the new paper "is an important and welcome contribution to the debate, which can help in arriving at a more balanced judgement".

Others question whether Reiding's details add much to the story. "There seem to be two camps: those who hate Debye and deplore his actions as president of the DPG, and those who think he was a saint," says Henk Lekkerkerker, a physical chemist at the Debye Institute in Utrecht. "Both opinions are misleading, and the professional historians paint a more subtle and accurate picture," he adds.

Morris concurs that "further evidence would be needed before this case could be proved beyond doubt", but, he says that "there was a rush to judgement that not only failed to take into account all the aspects of Debye's complex life, but also failed to give full weight to the ambiguous nature of life under Nazi rule".