Abstract
We study the stability of a hydrogen molecule H2 interacting with an octamer water cage (H2O)8, both in the D 2d and in the S 4 configurations. The H2 molecule was allowed to approach the water cage along its main symmetry directions, resulting in physisorbed final configurations, with binding energy 0.01–0.06 eV, depending on the starting geometry and the level of approximation used. The vibrational spectra of all stable configurations show an increase of both IR intensity and Raman activity below 300 cm−1, due to dimer–octamer interaction. Finally, we have also considered an H2 dimer inside a water octamer cage. In this case, we confirm a sizeable blue-shift of the H2 frequency, as has been recently found also for the H2·(H2O)12 cluster.
Acknowledgements
I.A.H. acknowledges support from Instituut voor de Aanmoediging van Innovatie door Wetenschap en Technologie in Vlaanderen (IWT) – Flemish region under grant no. IWT-161. G.G.N.A. wishes to thank the Department of Physics, University of Antwerp, for warm hospitality and for the stimulating environment.