MULTICRITICAL PHENOMENA FOR THE HYDROGEN MOLECULE AT THE LARGE-DIMENSION LIMIT

We show that symmetry breaking of the electronic structure configurati ons for the Hartree-Fock hydrogen molecule at the large-dimension limi t can be described as standard phase transitions. The phase diagram in the internuclear distance-nuclear charge plane shows three different stable phases corresponding to different electronic structure configur ations. This phase diagram is characterized by a bicritical point wher e the two continuous phase transition lines join a first order transit ion line.