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There will be a meeting of the Theory Journal Club next Wednesday: Speaker: Joan Adler, Technion, Israel Venue: Room 5, 12 - 1 pm, Wednesday 3rd September Queries: Chris Hamer Topic: Simulation of Solid Molecular Hydrogen - Models and Applications. Joan Adler, Technion Solid molecular hydrogen is a fascinating material, even though some may consider it to be less exotic than solid atomic hydrogen. It was intensively explored in the seventies and eighties, both in the laboratory and as theoretical/computational models. For some states, the hydrogen molecules behave like quadrupoles which preferentially orient perpendicular to each other, leading to an orientational ordering. Under the natural dilution of orthohydorgen molecules by the para form, this ordering disappears quite quickly, leading to a quadrupolar glass phase. A ``toy'' model known as the 3 state Potts antiferromagnet on the triangular lattice exibits a similar phase diagram, with transitions bounded by bootstrap percolation transitions. An introduction to these systems and all the models mentioned above as well as the relevance to hydrogen storage in fullerenes will be given. The model systems were studied with Horst Meyer and Richard Palmer, and the molecular hydrogen simulations were made by Or Cohen as a class project.