Investigating State Relocalisation in Mg and Mg Compounds

Continuum lowering predictions from standard plasma models have come under scrutiny in light of significant discrepancies with the measured continuum lowering at recent experiments. We attribute this to the difficulty in defining states as purely bound or purely free in average atom models. Here, we use the inverse participation ratio of valence states calculated using finite-temperature density function theory to study the localisation (“boundness”) of states in Mg and Mg compounds. We apply this with a hybrid Kohn-Sham scheme to perform calculations with electron temperatures in excess of 100 eV, investigating the effect of the density around the Mg sites on the recombination of the M-shell. It is found that the M-shell clearly relocalizes in isochorically heated Mg; however, in MgF₂, while peaks associated with the Mg M-shell form in the density of states, these states do not fully localise.