Aage Bohr, “Krigens år og atomvåbnenes perspektiver,” s. 184–206 i Niels Bohr: Hans liv og virke fortalt af en kreds af venner og medarbejdere (København: Schultz, 1964), on pp. 185–186.

Efter krigens udbrud og især efter Danmarks besættelse var man jo i København helt afskåret fra at følge de bestræbelser, der udfoldedes i de krigsførende lande på atomenergiens område. Forskellige rygter nåede dog hertil om de tyske bestræbelser, og indtrykket af, at man i Tyskland tillagde disse muligheder stor militær betydning, styrkedes ved besøg i København i efteråret 1941 af Werner Heisenberg og C.F. von Weizsäcker, der havde et nært personligt forhold til far fra deres tidligere deltagelse i det videnskabelige arbejde på Instituttet. De var i København i andet anliggende, men i en personlig samtale med far bragte Heisenberg problemet på tale. Far var meget tilbageholdende og gav udtryk for skepsis på grund af de store tekniske vanskeligheder, der måtte overvindes, men han fik det indtryk, at Heisenberg mente, at de nye muligheder kunne komme til at afgøre krigen, hvis denne trak ud.*

* I sin bog “Stærkere end Tusind Sole” fortæller Robert Jungk, at far under besættelsen skulle have fået forelagt en hemmelig plan fra tyske fysikere gående ud på, at man gennem en gensidig overenskomst med kolleger i de allierede lande skulle søge at hindre udviklingen af atomvåben. Det bør fastslås, at denne beretning savner ethvert grundlag i de faktiske begivenheder, idet der hverken under Heisenbergs eller ved et senere – ligeledes af Jungk omtalt– besøg i København af den tyske fysiker Hans Jensen var nogensomhelst tale om en sådan plan. Tværtimod bidrog, som allerede nævnt, den iøvrigt meget sparsomme kontakt med tyske fysikere under besættelsen til at styrke indtrykket af, at man fra de tyske myndigheders side tillagde atomenergiproblemerne stor militær betydning.

Aage Bohr, “The War Years and the Prospects Raised by the Atomic Weapons,” pp.  191–214 in Stefan Rozental (ed.): Niels Bohr: His life and work as seen by his friends and colleagues (Amsterdam: North-Holland Publishing Company, 1967), on p. 193.

After the outbreak of war and especially after the occupation of Denmark we in Copenhagen were completely cut off from following the allied nations’ efforts in the field of atomic energy. Various rumours reached us, however, of the German efforts, and the impression that in Germany great military importance was given to these possibilities was strenghtened by the visit to Copenhagen in the autumn of 1941 of Werner Heisenberg and C.F. von Weizsäcker. They were in Copenhagen on other business, but in a private conversation with my father Heisenberg brought up the question of the military applications of atomic energy. My father was very reticent and expressed his scepticism because of the great technical difficulties that had to be overcome, but he had the impression that Heisenberg thought that the new possibilities could decide the outcome of the war if the war dragged on.*

* In the book “Brighter than a Thousand Suns” by Robert Jungk it is asserted that the German physicists submitted a secret plan to my father, aimed at preventing the development of atomic weapons through a mutual agreement with colleagues in the allied countries. This account has no basis in the actual events, since there was no mention of any such plan either during Heisenberg’s visit, or during a later visit to Copenhagen – also mentioned by Jungk – of the German physicist Hans J.D. Jensen. On the contrary, the very scanty contact with the German physicists during the occupation contributed – as already mentioned – to strenghten the impression that the German authorities attributed great military importance to atomic energy.