Chemists Without Knowing It?

Abstract

This paper considers aspects of the chemistry-physics relationship from a historical perspective and with a focus on the entrance of quantum mechanics in twentieth-century chemistry. Traditionally, theoretical physics was widely regarded as epistemically superior to chemistry if also, from the chemists’ point of view, of little practical relevance. With the emergence of quantum chemistry in about 1930, the gulf widened as it seemed that the new discipline was more physics than chemistry. One way of investigating theoretically many-electron atoms was by means of the Hartree-Fock approximation method. The Møller-Plesset perturbation theory introduced in 1934 by a Danish and an American physicist was a refinement to the Hartree-Fock method. Although the Møller-Plesset theory was initially neglected – and is still neglected in the historiography of quantum chemistry – it came to play a most important role in later studies. Indeed, it is a prime example of what in sociological studies of science is known as a “sleeping beauty.” The paper discusses the historical context of the Møller-Plesset theory, concluding that, in a sense, its originators were “chemists without knowing it.”