High temperature driven transformation of iodine species in AFI and AEL channels: A comparative study

Abstract

Abstract The dynamic behavior study of iodine molecules in the confinement environment is a fundamental scientific issue of great interest. Here, we report a comparative study on the high temperature transformation of iodine species in AFI and AEL channels. No solid, liquid and gas phase transition sequence is observed as the bulk iodine. In the AFI channels, the iodine chains dissociate into the lying iodine molecules and then transform to the standing iodine molecules upon heating. However, the iodine species in AEL channels show different behaviors. The iodine chains, lying and standing molecules still exist under the similar heating conditions. Furthermore, we discuss the discrepancies in terms of the total energy of the confinement systems when one iodine molecule is placed in the channel with different orientations and at different positions. The calculated energy shows the standing configuration is the stable state in I@AFI system, while the standing and lying iodine are preferable in I@AEL system. The higher translational energy barrier and different stable configurations for iodine molecules in AEL channels are responsible for the discrepancies in structural transformation from that in AFI channels. This study makes us have a good knowledge of the influence of host-guest interaction in the confinement environment on the dynamic behavior of confined iodine molecules and provides a method for further manipulating and controlling iodine molecules.