The Right Answer for the Right Reason: My Personal Goal for Quantum Chemistry

A brief history of quantum theory is given to illustrate the barriers to progress caused by preconceived ideas. The biases in my own thinking which I had to overcome to approach the right answer for the right reason are discussed. This is followed by a personal autobiography illustrating how I have led a life of serendipity with no real sense of purpose. Chance events have shaped my life. The algorithms for which I am best known are briefly discussed. Then highlights from the many applications of theory to excited states, bonding in ice, spin properties and magnetism, (e,2e) shake-up spectra, and organic reactions are mentioned. This wide range of applications is mostly due to accidental collaboration with colleagues who sought my help. My real interest was in developing methods which could address these problems.

Quantum Narratives and the Power of Rhetorical Omission

John S. Bell openly questioned the dominance of an orthodox quantum interpretation that had seemingly raised the principle of indeterminism from an epistemological question to an ontological truth in the late 1920s. He understood the inevitability of indeterminism to be a theoretical choice made by the founding architects of quantum theory, not a fundamental principle of reality necessitated by experimental facts. As a result, Bell decried the general lull in quantum interpretation debates within the physics community, and in particular, the complete omission of Louis de Broglie’s deterministic pilot wave interpretation from all theoretical and pedagogical discourses. This paper reexamines the pilot wave’s rise, abandonment, and subsequent omission in the history of quantum theory. What emerges is not a straightforward story of victimization and hegemonic marginalization. Instead, it is a story that grapples with tensions between the polyphony of individual voices and a physics community’s evolving identity and consensus in response to particular sociopolitical and scientific contexts. At the heart of these tensions sits an international scientific community transitioning from a politically fractured and intellectually divergent community to one embracing a somewhat forced pragmatic convergence around rationally reconstructed narratives and concepts like the impossibility of determinism. The story of the pilot wave’s omission gives us a window into the inherent power that theoretical choice and a congealing rhetoric of orthodoxy have on a scientific community’s consensus, pedagogical canons, and the future development of science itself.

Between Accuracy and Manageability: Computational Imperatives in Quantum Chemistry

This article explores the place of computation in the history of quantum theory by examining the development of several approximation methods to solve the Schröödinger equation without using empirical information, as these were worked out in the years from 1927 to 1933. These ab initio methods, as they became known, produced the results that helped validate the use of quantum mechanics in many-body atomic and molecular systems, but carrying out the computations became increasingly laborious and difficult as better agreement between theory and experiment was pursued and more complex systems were tackled. I argue that computational work in the early years of quantum chemistry shows an emerging practice of theory that required human labor, technological improvement (computers), and mathematical ingenuity.

Les tensions actuelles de l'histoire des sciences

Les débats passionnés soulevés dans l'épistémologie anglo-américaine au milieu des années soixante par La Structure des révolutions scientifiques Kuhn, 1962), connaissent actuellement en France un intérêt remarquable. Les spécialistes de l'histoire des sciences préfèrent aujourd'hui associer le nom de Thomas Kuhn à l'Archive for the History of Quantum Theory, qu'il a patiemment réunie, et à son histoire des origines de la physique quantique (Kuhn, 1978). Pour tous les sociologues, épistémologues, historiens et scientifiques qui ont lu La Structure, le nom de Kuhn restera au contraire indissociablement lié à l'apparition d'un puissant modèle sociologique de l'histoire des sciences, dont ce petit-grand livre fut le véhicule.