Peter Joseph William Debye ForMemRS[1] (/dɪˈbaɪ/ dib-EYE;[2] born Petrus Josephus Wilhelmus Debije,[a] Dutch: [ˈpeːtrʏz dəˈbɛiə]; March 24, 1884 – November 2, 1966)[3][4] was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry.

This was followed by moves to Utrecht in 1912,[5] to Göttingen in 1913, to ETH Zurich in 1920, to University of Leipzig in 1927, and in 1934 to Berlin, where, succeeding Einstein, he became director of the Kaiser Wilhelm Institute for Physics (now named the Max-Planck-Institut) whose facilities were built only during Debye's era.

Also in 1912, he extended Albert Einstein's theory of specific heat to lower temperatures by including contributions from low-frequency phonons.

In 1914–1915, Debye calculated the effect of temperature on X-ray diffraction patterns of crystalline solids with Paul Scherrer (the "Debye–Waller factor").

Although an improvement was made to the Debye–Hückel equation in 1926 by Lars Onsager, the theory is still regarded as a major forward step in our understanding of electrolytic solutions.

After leaving Germany in early 1940, Debye became a professor at Cornell, chaired the chemistry department for 10 years, and became a member of Alpha Chi Sigma.

Rispens discovered documents that, as he believed, were new and proved that, during his directorship of the Kaiser Wilhelm Society, Debye was actively involved in cleansing German science institutions of Jewish and other "non-Aryan elements".

Many biographies[1][14][15] published before Rispens' work, state that Debye moved to the US because he refused to accept German citizenship forced on to him by the Nazis.

He planned his departure from Germany during a visit with his mother in Maastricht in late 1939, boarded a ship in Genoa in January 1940 and arrived in New York in early February 1940.

Van Ginkel[16] investigated 1940 FBI reports on this matter and traced the "reliable source" to a single letter directed to Einstein and written by someone whose name is lost.

Predating Rispens' work, and in contrast to it, an article by Rechenberg[19] appeared 18 years earlier concerning Debye's letter.

In his article he cites scholars who point out that the DPG was able to retain their threatened staff as long as could be expected under increasing pressure from the Nazis.

Also Einstein, with his enormous prestige, was still alive, as were other Jewish scientists such as Lise Meitner and James Franck who both knew Debye intimately.

They quote the response of the Reich University Teachers League (a National Socialist organization) to the Debye letter: Obviously the German Physical Society is still very backward and still clings tightly to their dear Jews.

It is in fact remarkable that only "because of circumstances beyond our control" the membership of Jews can no longer be maintained In May 2006,[24] the Dutch Nobel Prize winner Martinus Veltman who had written the foreword to the Rispen book, renounced the book's description of Peter Debye, withdrew his foreword, and asked the Board of Directors of Utrecht University to rescind their decision to rename the Debye Institute.

The earliest of these investigations, carried out by the Cornell University's department of Chemistry and Chemical Biology released a report[25] on 31 May 2006, which states that: Based on the information to-date, we have not found evidence supporting the accusations that Debye was a Nazi sympathizer or collaborator or that he held anti-Semitic views.

It goes on to declare: Thus, based on the information, evidence and historical record known to date, we believe that any action that dissociates Debye's name from the Department of Chemistry and Chemical Biology at Cornell is unwarranted.

[28] In May 2007, the universities of Utrecht and Maastricht announced that a new committee headed by Jan Terlouw would advise them regarding the name change.

Also, in the beginning of 2007 an official report was announced, to be published by the NIOD and authorized by the Dutch Education Ministry (then scheduled for fall 2007).

It concludes that Debye's actions in 1933–45 were based on the nineteenth-century positivist view of science which saw research in physics as generating blessings for humankind.

[30] The NIOD report also concludes that Debye felt obliged to send the letter and that it was, for him, simply a confirmation of an existing situation.

The report argues that Debye, in the Third Reich, developed a survival method of ambiguity which allowed him to pursue his scientific career despite the political turmoil.

The Commission pointed out that the Royal Dutch Academy of Sciences also took away Albert Einstein's honorary membership, emphasizing the circumstances in which these decisions had been taken.

The Commission stated that now, seventy years later, no judgment can be made concerning the decision of Debye to sign this letter in the exceptionally difficult circumstances in which he then found himself.

Nevertheless, the Commission describes the DPG letter as an extraordinarily unpleasant fact, forming a dark page in his life history.

Reiding also offers an explanation for Debye's hasty departure on 16 January 1940 for the United States: the date coincided with the planned (but later delayed) German invasion of the Netherlands a day later, information possibly provided to him by Rosbaud.