Density functional study on Am(III)/Eu(III) selectivity using crown ether type ligands

Density functional theory calculations were applied to understand the selectivity between Am 3+ and Eu 3+ ions with the crown ethers type ligands. 18C6 is predicted to form the most stable complex with Eu 3+ and show the higher stability for Am 3+ over Eu 3+ , being consistent with previously reported Am 3+ /Eu 3+ selectivity. We modeled N- and S-donor complexes by using framework of 18C6 complex and analyzed the complexation Gibbs energies, indicating that 18C6 with N-donor atoms is suitable for both complexation and higher Am 3+ stability over Eu 3+ due to the stronger covalent interaction.