The Potential Energy Surface in Molecular Quantum Mechanics

TL;DR

This paper discusses the origin, development, and current uncertainties of the Potential Energy Surface concept in molecular quantum mechanics, highlighting its foundational role and the debates surrounding its present status.

Contribution

It provides a historical and conceptual analysis of the PES, questioning its assumed calculability and current theoretical standing in molecular quantum mechanics.

Findings

PES is central to understanding chemical reactions and spectroscopy.

The article questions the certainty of PES's current theoretical status.

Historical development of PES from Old Quantum Theory to present.

Abstract

The idea of a Potential Energy Surface (PES) forms the basis of almost all accounts of the mechanisms of chemical reactions, and much of theoretical molecular spectroscopy. It is assumed that, in principle, the PES can be calculated by means of clamped-nuclei electronic structure calculations based upon the Schr\"{o}dinger Coulomb Hamiltonian. This article is devoted to a discussion of the origin of the idea, its development in the context of the Old Quantum Theory, and its present status in the quantum mechanics of molecules. It is argued that its present status must be regarded as uncertain.