Nuclear motion is classical

TL;DR

This paper supports the idea that nuclear motion in molecules can be accurately modeled using classical Newtonian physics rather than quantum mechanics, based on theoretical and experimental considerations.

Contribution

It provides a substantiation for classical treatment of nuclear motion in ab-initio molecular dynamics, clarifying the role of temperature effects and zero-point energy.

Findings

Classical Newton dynamics effectively describe nuclear motion.

Experimental considerations are crucial for distinguishing quantum from classical behavior.

Zero-point energy effects must be carefully controlled in experiments.

Abstract

The notion from ab-initio molecular dynamics simulations that nuclear motion is best described by classical Newton dynamics instead of the time-dependent Schr{\"o}dinger equation is substantiated. In principle a single experiment should bring clarity. Caution is however necessary, as temperature dependent effects must be eliminated when trying to determine the existence of a zero-point energy.