Quantum chemistry is the branch of chemistry whose primary focus is the application of quantum mechanics to chemical systems at the molecular level. Precisely due to its peculiar position between chemistry and physics, in the last times it has begun to engage the interest of the philosophers of chemistry. Nevertheless, in this philosophical field, quantum chemistry has been studied mainly from a historical viewpoint or from a perspective interested on methodological issues. By contrast, the question that will guide this article is: what kind of ontic items are those studied by quantum chemistry? In order to develop the argumentation, first the relevance of the ontological questions will be addressed. Then, it will be considered in what measure the Born-Oppenheimer approximation and the quantum-chemistry concept of electron fit in the quantum theoretical context. Finally, some issues about what quantum chemistry refers to will be discussed.
Quantum chemistry is the branch of chemistry whose primary focus is the application of quantum mechanics to chemical systems at the molecular level. Precisely due to its peculiar position between chemistry and physics, in the last times it has begun to engage the interest of the philosophers of chemistry. Nevertheless, in this philosophical field, quantum chemistry has been studied mainly from a historical viewpoint or from a perspective interested on methodological issues. By contrast, the question that will guide this article is: what kind of ontic items are those studied by quantum chemistry? In order to develop the argumentation, first the relevance of the ontological questions will be addressed. Then, it will be considered in what measure the Born-Oppenheimer approximation and the quantum-chemistry concept of electron fit in the quantum theoretical context. Finally, some issues about what quantum chemistry refers to will be discussed.
espanolQuimica cuantica es la rama de la quimica que se ocupa principalmente de la aplicacion de la mecanica cuantica a los sistemas quimicos a un nivel molecular. Gracias a su peculiar posicion entre la quimica y la fisica, ha comenzado a ser una disciplina de interes para los filosofos de la quimica. Sin embargo, en el ambito filosofico, la quimica cuantica se ha estudiado principalmente, desde una perspectiva historica o desde cuestiones metodologicas. En contraste, la pregunta que guia este articulo es: ?que clase de entidades son estudiadas por la quimica cuantica? Para desarrollar mi argumento, discutire, en primer lugar, la importancia de las preguntas ontologicas. Despues, considerare en que medida la aproximacion Born-Oppenheimer y el concepto de electron de la quimica cuantica se ajustan al contexto teorico cuantico. Finalmente, discutire algunas cuestiones acerca de a que se refiere la quimica cuantica. EnglishQuantum chemistry is the branch of chemistry whose pri-mary focus is the application of quantum mechanics to chemi-cal systems at the molecular level. Precisely due to its peculiar position between chemistry and physics, in the last times it has begun to engage the interest of the philosophers of chemistry. Nevertheless, in this philosophical field, quantum chemistry has been studied mainly from a historical viewpoint or from a per-spective interested on methodological issues. By contrast, the question that will guide this article is: what kind of ontic items are those studied by quantum chemistry? In order to develop the argumentation, first the relevance of the ontological questions will be addressed. Then, it will be considered in what measure the Born-Oppenheimer approximation and the quantum-chem-istry concept of electron fit in the quantum theoretical context. Finally, some issues about what quantum chemistry refers to will be discussed.
The concept of atomic and molecular orbitals has been a fundamental pillar in modern chemistry, shedding light on the structures and reactivity of chemical compounds. This article examines the evolution and significance of orbital theory, its applications in chemistry, and the ongoing debate about the existence of orbitals from both physics and chemistry perspectives. Philosophical aspects related to the ontology of orbitals are explored, emphasizing the complex interplay between mathematical abstractions and tangible reality. The multifaceted nature of orbitals, their role in quantum mechanics, and their implications for understanding the quantum realm are discussed. While the debate surrounding the ontological status of orbitals remains ongoing, it highlights the profound nature of inquiries into the fundamental essence of reality. This exploration underscores the significance of continuous research and discourse in advancing our understanding of these fundamental constituents of the quantum world.
Philosophers mainly refer to quantum chemistry in order to address questions about the reducibility or autonomy of chemistry relative to quantum physics, and to argue for or against ontological emergence. To make their point, they scrutinize quantum approximations and formalisms as if they were independent of the questions at stake. This paper proposes a return to history and to the laboratory so as to emphasize how quantum chemists never cease to negotiate the relationships between a molecule, its parts, and its environment. This investigation will enable us to draw methodological conclusions about the role of history within philosophical studies, and to examine how quantum chemistry can clarify important philosophical and mereological issues relatedto the emergence/reduction debate, or to the way instruments and contexts are involved in the material making and the formal description of wholes and parts.
Abstract Philosophers have claimed that: (a) Born–Oppenheimer approximation methods for solving molecular Schrödinger equations violate the Heisenberg uncertainty relations; therefore, (b) ‘quantum chemistry’ is not fully quantum; and (c) therefore chemistry does not reduce to physics. This paper analyses the reasoning behind Born–Oppenheimer methods and shows that they are internally consistent and fully quantum mechanical, contrary to (a)–(c). Our analysis addresses important issues of mathematical rigour, physical idealization, reduction, and classicality in the quantum theory of molecules, and we propose an agenda for the philosophy of quantum chemistry more grounded in scientific practice.
Abstract Despite the successful development of quantum chemistry, the deep breakdown between the conceptual basis of standard quantum mechanics and some implicit ontological assumptions of quantum chemistry is only rarely acknowledged. In fact, in the framework of standard quantum mechanics, quantum systems are not individual objects in the philosophical sense: they cannot be individualized by their positions in space and time and, as a consequence, they have no trajectories. By contrast, the basic magnitude in quantum chemistry is the electronic density, which is commonly interpreted in terms of the definite positions occupied by the individual electron in its motion around the nucleus. In the present paper, it will be argued that Bohmian Mechanics offers an ontological picture that is much closer to the quantum chemists’ way of conceiving their research field.
The aim of the present paper is to analyze the problem of the relationship between\nchemistry and physics, by focusing on the widely discussed case of the atomic orbitals.\nWe will begin by remembering the difference between the physical and the chemical interpretation\nof the concept of orbital. Then, we will refer to the claim made in 1999 that\natomic orbitals have been directly imaged for the first time. On this basis, we will analyze\nthe problem from a new approach, by comparing the concept of orbital used in physics with\nthe concept of orbital used in chemistry. Such an analysis will allow us to argue for an ontological\npluralism that admits the coexistence of different ontologies without priorities or\nmetaphysical privileges. From this philosophical framework, the concepts of chemical orbital\nand physical orbital correspond to two different ontologies. As a consequence, chemical orbitals\nare real entities belonging to the ontology of molecular chemistry, and can be observed\nlike any other entity not belonging to the quantum mechanical ontology.