See slides here

  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


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.