Computational design of multi-states monomolecular device using molecular hydrogen and C$_{20}$ isomers

We perform detailed calculations for the interaction of molecular hydrogen with C$_{20}$ isomers in the framework of density functional theory method. The adsorption of H$_{2}$ outside the C$_{20}$-e isomer with parallel orientation with respect to the plane of the hexagon is found to be the most stable adsorption configuration. Thus this might have potential for the hydrogen storing. We have also investigated the number and the position of adsorption sites in the pentagon for the parallel configurations of the H$_{2}$/C$_{20}$ systems. We find two stable configurations of the molecule for the C$_{20}$-bowl isomer that have a small difference in energy. Thus, surprisingly, despite their apparent simplicity these H$_{2}$/C$_{20}$-bowl systems are shown to exhibit the flip-flop motion by a small current pulse. Hence, it might be a candidate for multi-states monomolecular device. Convenient experimental techniques such as field emission microscopy are proposed to test these predictions. This work was supported by the Azad University of Qaemshahr.