Quantum thermodynamics of (H2)x@C60 [x=1–2x=1–2]: A path integral Monte Carlo study

The thermodynamic properties of H2 and (H2)2 inside C60 were computed using the path integral formalism. In accordance with experimental data, H2@C60 is thermodynamically stable in a wide range of temperatures due to energetic factors. Variations in the molecular hydrogen–fullerene interaction energy were considered in order to increase the stability of the monomeric system. For (H2)2@C60 no stable states were observed in the temperature range studied or in any reasonable modification in the molecular hydrogen–fullerene interaction parameter. Modification of the attractive part of the molecular hydrogen–fullerene interaction stabilized the dimeric system.

► Thermodynamic information of molecular hydrogen entrapped in fullerene.
► One hydrogen molecule trapped in C60 is energetically stable.
► Two hydrogen molecules trapped are not thermodynamic stable.
► Increments in the attractive part of the hydrogen/C60 potential stabilized the entrapped molecules.