On the Quantum Theory of Molecules

TL;DR

This paper questions the traditional assumption that potential energy surfaces derived from quantum mechanics accurately represent molecular behavior, proposing instead that they are effective modifications for chemical modeling.

Contribution

It challenges the conventional view of PES construction from quantum eigensolutions, suggesting a reinterpretation as a modified approach for chemical applications.

Findings

PES construction from quantum eigensolutions may be unfounded.

Quantum mechanical calculations are routine but may not directly produce accurate PES.

PES should be viewed as an effective modification rather than a direct derivation.

Abstract

Transition state theory was introduced in the 1930s to account for chemical reactions. Central to this theory is the idea of a potential energy surface (PES). It was assumed that such a surface could be constructed using eigensolutions of the Schr\"{o}dinger equation for the molecular (Coulomb) Hamiltonian but at that time such calculations were not possible. Nowadays quantum mechanical ab-initio electronic structure calculations are routine and from their results PESs can be constructed which are believed to approximate those assumed derivable from the eigensolutions. It is argued here that this belief is unfounded. It is suggested that the potential energy surface construction is more appropriately regarded as a legitimate and effective modification of quantum mechanics for chemical purposes