Orientational quantum melting of linear rotors pinned onto surfaces
Department of Chemistry, Columbia University - New York, NY 10027, USA
Accepted: 3 September 1998
Ground-state properties of the quantum anisotropic-planar-rotor (QAPR) model, which describes orientational ordering of linear molecules on graphite surfaces, are investigated by means of diffusion Monte Carlo. It is found that a quantum melting of the long-range orientational ordering occurs at a rotational constant in units of the quadrupolar coupling constant. This result together with the finite-temperature simulations of Martonak et al. (Phys. Rev. E, 55 (1997) 2184) shows that the QAPR model exhibits reentrance.
PACS: 64.60.Cn – Order-disorder transformations; statistical mechanics of model systems / 67.40.Db – Quantum statistical theory; ground state, elementary excitations / 82.20.Wt – Computational modeling; simulation
© EDP Sciences, 1998