On nonadiabatic calculation of dipole moments

TL;DR

This paper critiques a recent nonadiabatic dipole moment calculation, highlighting inconsistencies with established theoretical principles and clarifying the correct approach.

Contribution

It identifies issues in a recent non Born--Oppenheimer method for dipole moments and clarifies the proper theoretical framework.

Findings

The recent calculation is inconsistent with the Hellmann--Feynman theorem.

The paper clarifies the correct nonadiabatic approach for dipole moments.

It points out obscure points in the previous method.

Abstract

We show that a recent non Born--Oppenheimer calculation of dipole moments exhibits obscure points and is not consistent with the well known Hellmann--Feynman theorem.