Further Monte Carlo studies of the rotation-libration transition in solid H2under pressure

✍ Scribed by I. Aviram; S. Goshen; R. Thieberger

• Publisher: Springer US
• Year: 1981
• Tongue: English
• Weight: 395 KB
• Volume: 43
• Category: Article
• ISSN: 0022-2291
• DOI: 10.1007/bf00115615

✦ Synopsis

The pressure-induced transition in solid para-H2 from free rotation of molecules to libration around the three-fold axes of the fcc structure is calculated using a completely anisotropic interaction potential of the form Vii = ~m Cm(rii)Y2m(l)i)Y2-m(l~i) including quadrupole-quadrupole and repulsive valence interactions. The rotational part of the Hamiltonian is assumed to be operating on a Jastrow-type wave function, including two variational parameters. The variational integrals are evaluated by a Monte Carlo procedure. The orientational order parameter in the low-density region increases very gradually with increasing density, until a sharp lump (indicating first-order) is observed at the transition density corresponding to R/Ro = 0.5775, where Ro is the nearest neighbor distance at zero pressure. This is 60 % higher than the density obtained in previous work.