January 7, 2002 By JAMES GLANZ The leader of the Nazi atomic bomb program, Werner Heisenberg, revealed its existence in September 1941 in a meeting in Copenhagen with a scientist who later became part of the Manhattan Project, the Allied effort to produce the bomb, according to secret documents cited in a London newspaper yesterday. But contrary to several historical accounts of the meeting and major themes of an award-winning play, "Copenhagen," Heisenberg never expressed moral qualms about building a bomb for Hitler or hinted that he might be willing to sabotage the project, the documents reveal. Some of the new information about the documents - especially a letter that Niels Bohr, the scientist with whom Heisenberg met, wrote but never sent - was reported yesterday by The Times of London, in an article citing Dr. Finn Aaserud, director of the Niels Bohr Archive in Copenhagen. Dr. Aaserud is one of the few people outside the Bohr family who have seen the letter, which may be the only way to learn what happened at a meeting that is one of history's enduring mysteries. Bohr died in 1962, and Heisenberg died in 1976; both were Nobel laureates and considered among the greatest physicists. "Essentially, the letter shows that he told Bohr that it was possible that the war would be won with atomic weapons, indicating that he was involved in such work," Dr. Aaserud said. The only other living person outside the Bohr family known to have read the letter is Dr. Gerald Holton, an emeritus professor of physics and the history of science at Harvard. Dr. Holton declined yesterday to describe the letter fully, citing confidentiality agreements with the Bohr family. But he said that "Dr. Aaserud's report about some of its content is quite coherent with what we know" from other sources, including statements by one of Bohr's sons, the physicist Aage Bohr. Dr. Holton said, "It is significant that Dr. Aaserud does not mention that any moral scruples or intention to sabotage the bomb project were reasons for Heisenberg's visit to Bohr." Historians and scientists have argued for decades over why Heisenberg never succeeded in building an atomic bomb for Hitler. But the journalist Thomas Powers, author of the 1993 book "Heisenberg's War: The Secret History of the German Bomb," has argued that Heisenberg sabotaged the project. In Mr. Powers's view, Heisenberg went to Copenhagen to make a deal with Bohr: The Germans would not develop the bomb if Allied scientists did not, either. The play "Copenhagen," by Michael Frayn, was inspired by Mr. Powers's book. That view of Heisenberg has always generated skepticism among some historians. The new information is likely to solidify a less favorable view, that Heisenberg simply failed despite his best efforts, said David Rhodes, the author of a history of the Manhattan Project, "The Making of the Atomic Bomb" (1986). "This letter confirms what I think was always pretty clear in the record, and that is that Heisenberg was not making some deal with Bohr," Mr. Rhodes said. "He was trying to find out what Bohr knew. He was trying to do a little espionage." Dr. Jeremy Bernstein, a theoretical physicist and author of "Hitler's Uranium Club," a 2001 book on secret recordings of members of the German bomb program, said the letter appeared to support his own criticism of Heisenberg's motives. "This is exactly what Aage Bohr has been saying all along," Dr. Bernstein said. Mr. Powers did not respond to messages seeking comment left on his answering machine yesterday. Dr. Holton also shed new light on why Bohr suddenly cut off the meeting and why it destroyed what had been Bohr's lifelong friendship with Heisenberg. Though some have attributed Bohr's reaction to anger, another explanation is more likely, Dr. Holton said. "The first thing that would come to mind is not anger but deep fright," Dr. Holton said of Bohr's reaction to learning of a Nazi bomb program. "He understood what that would mean for civilization." Many historians have praised the historical studies that Mr. Frayn undertook before writing the play. Still, in contrast to the complex Heisenberg of the play, the physicist in reality may have been easier to understand, Dr. Bernstein said. Mr. Frayn "wants to see both sides of the story," Dr. Bernstein said, "and there's some stories where there's only one side. This may be one of them." Copyright 2001 The New York Times Company