The water-dimer formation and its encapsulation into D-2(22)-C-84 and D-2d(23)-C-84 fullerenes is evaluated. The water-dimer populations are computed using the potential-energy change from the G3 theory and anharmonic partition functions from the MP2/AUG-cc-pVQZ approach.
The encapsulation energetics is treated at the M06-2X/6-31++G** level and it is found that the water-dimer storage in C-84 is attractive, yielding an energy gain of more than 10 kcal mol(-1). This substantial encapsulation energy together with the computed temperature increase of the water-dimer population in the saturated steam suggests that the (H2O)(2)@C-84 endohedrals could be produced in a high-temperature/high-pressure approach similarly to encapsulation of rare gases in fullerenes.