During Houtermans's employment at the Physikalisch-Technische Reichsanstalt (PTR), he got himself into serious trouble as a result of his habit of being a chain-smoker and suffering great distress if he did not have a supply of tobacco. On official PTR stationery, he wrote to a Dresden cigarette manufacturer to obtain a kilogram of Macedonian tobacco, claiming that he could extract heavy water from the tobacco, and thus that it was "kriegswichtig", i.e., important for the war effort. When he had smoked the tobacco, he again wrote for more, however, the letter fell into the hands of an official at the PTR, who had him fired. Werner Heisenberg and Carl Weizsäcker came to the rescue of Houtermans and arranged an interview for him with Walter Gerlach, the plenipotentiary (Bevollmächtiger) for German nuclear research under the Reich Research Council. As a result, Houtermans moved to Göttingen in 1945, where Hans Kopferman and Richard Becker got him positions at the Institut für Theoretische Physik and II. Physikalischen Institut der Universität Göttingen.