Q-dependence of the inelastic neutron scattering cross section for molecular spin clusters with high molecular symmetry

TL;DR

This paper demonstrates that the Q-dependence of inelastic neutron scattering in high-symmetry molecular nanomagnets is entirely dictated by their molecular symmetry, providing a formalism linking symmetry and scattering interference.

Contribution

It introduces a general formalism connecting molecular symmetry with interference terms in neutron scattering, specifically for cyclic and star-like spin clusters.

Findings

Q-dependence is determined by molecular symmetry in high-symmetry clusters.

Developed a formalism linking spatial symmetry and interference effects.

Applied the formalism to Cr8 and Fe4 molecular clusters.

Abstract

For powder samples of polynuclear metal complexes the dependence of the inelastic neutron scattering intensity on the momentum transfer Q is known to be described by a combination of so called interference terms. They reflect the interplay between the geometrical structure of the compound and the spatial properties of the wave functions involved in the transition. In this work, it is shown that the Q-dependence is strongly interrelated with the molecular symmetry of molecular nanomagnets, and, if the molecular symmetry is high enough, is actually completely determined by it. A general formalism connecting spatial symmetry and interference terms is developed. The arguments are detailed for cyclic spin clusters, as experimentally realized by e.g. the octanuclear molecular wheel Cr8, and the star like tetranuclear cluster Fe4.