How a magnetic field changes the way molecules vibrate

Overview

The problem

A steady magnetic field could be used to drive molecular vibrations and, through them, control chemistry. So far, how nuclei move under such a field has mostly been studied with classical approximations.

The approach

This work introduces a quantum dynamics method in which the protons are treated quantum mechanically along with the electrons, using orbitals adapted to the magnetic field (London orbitals), so their motion can be followed in real time.

What it found

Simulations of HCN and formaldehyde (H₂CO) show that the effect depends on how the field is oriented relative to the symmetry of each vibration. The field couples vibrations that would otherwise stay separate.

Abstract

Harnessing a static magnetic field to drive molecular vibrations presents a promising avenue for controlling chemical processes. However, the coupling of nuclear dynamics with an external magnetic field has largely been explored only through classical approximations. In this work, we introduce a time-dependent quantum dynamics formalism based on London nuclear–electronic orbitals, enabling the simulation of magnetic field-driven quantum dynamics. Through simulations of HCN and H₂CO molecules, we provide a detailed analysis of how the relative orientation of the magnetic field and vibrational symmetry influence the resulting quantum dynamics. Our findings reveal field-induced mode couplings and symmetry-dependent effects, offering new insights into the role of magnetic fields in vibrational control.

Simulating Magnetic Field-Driven Real-Time Quantum Dynamics Using London Nuclear–Electronic Orbital Approach

Overview

The problem

The approach

What it found

Abstract