Abstract
Density-functional theory (DFT) calculations are reported for Sm@C-74, namely for Sm encapsulation in the IPR (isolated pentagon rule) C-74 cage and in two C-74 cages with a pentagon-pentagon junction. Their relative thermodynamic production yields are evaluated using the DFT calculated terms and it is shown that the IPR-based Sm@C-74 endohedral prevails at relevant temperatures in agreement with observation, however, isolation of a minor isomer could be possible.