Exploring the potential of magnesium clusters as effective adsorbents for gaseous radioactive iodine in nuclear energy applications

The interaction of molecular iodine on Mg_n (n = 2–18) clusters has been investigated using first-principles calculations. Structural, adsorption energy and electronic properties of these systems are reported. After structure optimization, the iodine molecule undergoes dissociative adsorption, where the I–I covalent bond of molecular iodine is broken and the dissociative iodine atoms adsorb on the surfaces of the magnesium clusters. The adsorption energy ranging from − 4.335 to − 5.740 eV indicates the chemisorption of I on Mg_n clusters. In the same way, for n > 4, Mg-I compounds have bond lengths of 2.694 to 2.937 Å forming ionic bonds and the values of charge transfer in Mg_nI₂ reach − 0.829 to − 0.977 e. The projected density of states (PDOS) of Mg₇I₂, which has the highest absolute adsorption energy, and Mg₁₆I₂, which has the highest amount of charge transfer, demonstrate the strong hybridization between the Mg 3s and the I 5p orbitals. Overall, the change in electronic structure suggests that Mg_n clusters might serve as promising adsorbents for the removal of gaseous radioactive iodine.