OPPENHEIMER, J. Robert, and BORN, Max, Zur Quantentheorie der Molekeln [OFFPRINT FROM:] Annalen der Physik, Vol. 84, No. 20 (Johann Ambrosius Barth, Leipzig), 1927

145x225mm; pp. 457–484

The Born-Oppenheimer Apporoximation: the theoretical foundation of quantum chemistry. Exceptionally scarce offprint (‘Sonderdruck’) of Oppenheimer's most influential paper: “the foundation for virtually all subsequent theoretical and computational studies of chemical binding and reactivity” (Tully, ‘Perspective on “Zur Quantentheorie der Molekeln”‘). Aside from its significance in molecular science, the paper also marks a turning point in Oppenheimer’s biography. In 1926 he had travelled to Göttingen to work with Max Born, and had quickly “become obsessed with what he called the ‘miracle’ of quantum mechanics” (Bird & Sherwin, American Prometheus). In the spring of 1927, at Werner Heisenberg's instigation, Oppenheimer attempted to use quantum theory to explain (in his own words) “why molecules were molecules”. When he shared his results with Born, the great German physicist had suggested a co-authored paper. Oppenheimer’s initial draft was too terse for Born, however, and so a lot of what Oppenheimer considered to be ‘padding’ was introduced. Hence, what should be the 'Oppenheimer Approximation' became the 'Born-Oppenheimer Approximation'. The essence of the Approximation is to neglect the motion of atomic nuclei when describing the electrons in a molecule. This is possible because of the huge discrepancy in mass between nuclei and electrons, and the consequent difference in in the rate of motion, with nuclei responding to change and moving more slowly. The paper has had wide ranging inlfuence and was also part of Oppeheimer’s first flourishing. As Bird and Sherwin put it: “Göttingen was the scene of Oppenheimer’s first real triumph as a young man coming of age.” Near fine condition: clean and unmarked, with a neat contemporary paper backstrip. No copies of the offprint located in libraries worldwide.