When chemistry and physics meet: the problem of optical isomerism

JUAN CAMILO MARTÍNEZ GONZÁLEZ; FORTÍN SEBASTIAN

Buenos Aires

Workshop; Identity, indistinguishability and non-locality in quantum physics; 2017

John Templeton Foundation - UBA - CONICET

In the present paper we address the problem of optical isomerism embodied in the socalled "Hund´s paradox", which points to the difficulty to account for chirality by means of quantum mechanics. In particular, we explain the answer to the problem proposed by the theory of decoherence. The purpose to this article is to challenge this answer on the basis of a conceptual analysis of the phenomenon of decoherence, that reveals the limitations of the theory of decoherence to solve the difficulties posed by optical isomerism and, in general, by quantum measurement.The question about whether the quantum formalism can account for optical isomerism concerns philosophy of chemistry for (at least) three reasons. First, it introduces an interesting case for the debate about the relation between physics (quantum mechanics) and chemistry (molecular chemistry), which has been the focus of many philosophical works in recent years. Second, and related to the previous point, the analysis of the paradox can enrich the discussion about whether quantum mechanics can provide an explanation of molecular structure. Third, since some approaches attribute the origins of the paradox to a focus on isolated molecules, the solution is believed to be found in considering molecules in interaction; these views pose a relevant question to the ontology of chemistry: is chirality an intrinsic property of a molecule? These three problematic matters make the resolution of the Hund paradox an issue of the utmost importance for the philosophy of chemistry.