In 1935 teller was invited to the United States to become a Professor of Physics at the George Washington University. He was working in the fields of quantum. molecular and nuclear physics. After he became a naturalized citizen he became very much interested in the use of nuclear energy. One of the single most important things contributions that Teller did was the elucidation of Jahn-Teller Effect. "This described the geometrical distortion that electrons clouds undergo in certain situations; that plays prominently in the description of chemical of chemical reactions of metals and in particular the coloration of certain metallic dyes. In collaboration with Brunauer and Emmett, Teller also made an important contribution to surface physics and chemistry: the so-called Brunauer-Emmett-Teller isotherm." (www.atomicarchive.com) In 1942 Teller was invited to be part of Oppenheimer's summer planning semeinar at UC Berkeley for the origins of the Manhattan Project. At first he worked with Leo Szilard in Chicago and then went to work with the people at Los Alamos in the Theoretical Physics division. Even being located here his obsession with H-bombs caused tension with other scientist. During Oppenheimer's security clearance hearings in 1954 that the final rift occurred between Teller and many of his scientific colleagues. At the hearing Teller stated, " I feel I would prefer to see the vital interests of this country in hands that I understand better and therefore trust more."