Electronic structure of the molecule based magnet Cu PM(NO3)2 (H2O)2

TL;DR

This study uses density functional theory to analyze the electronic structure and magnetic interactions in the molecule-based magnet Cu PM(NO3)2 (H2O)2, revealing the nature of exchange coupling and hyperfine interactions.

Contribution

It provides detailed computational insights into the magnetic exchange mechanisms and hyperfine parameters in a molecule-based antiferromagnetic chain compound.

Findings

Exchange coupling is antiferromagnetic and aligns with experimental data.

Charge delocalization on nitrogen atoms influences magnetic coupling.

Computed hyperfine parameters agree with recent NMR experiments.

Abstract

We present density functional calculations on the molecule based S=1/2 antiferromagnetic chain compound Cu PM(NO3)2 (H2O)2; PM = pyrimidine. The properties of the ferro- and antiferromagnetic state are investigated at the level of the local density approximation and with the hybrid functional B3LYP. Spin density maps illustrate the exchange path via the pyrimidine molecule which mediates the magnetism in the one-dimensional chain. The computed exchange coupling is antiferromagnetic and in reasonable agreement with the experiment. It is suggested that the antiferromagnetic coupling is due to the possibility of stronger delocalization of the charges on the nitrogen atoms, compared to the ferromagnetic case. In addition, computed isotropic and anisotropic hyperfine interaction parameters are compared with recent NMR experiments.