6533b870fe1ef96bd12cf974
RESEARCH PRODUCT
Monte Carlo investigation of head-tail ordering of CO monolayers on graphite
Peter NielabaSurajit SenguptaKurt BinderD. Marxsubject
Phase transitionCondensed matter physicsChemistryMonte Carlo methodAb initioSurfaces and InterfacesCondensed Matter PhysicsHeat capacitySurfaces Coatings and FilmsDipoleMaterials ChemistryIsing modelGround statePair potentialdescription
Abstract Heat capacity measurements recently showed that CO physisorbed on graphite undergoes a head-tail ordering transition at roughly 5 K. The present paper is a detailed Monte Carlo study of this phase transition and the ordered state. The simulations are based on an ab initio pair potential and rely crucially on a thorough finite-size scaling study of various quantities. In agreement with experiments we find that the transition belongs to the universality class of the Ising model in two dimensions. We go beyond experimental knowledge by revealing the particular ferrielectric structure of the ground state, and show that the transition is due to the molecule's shape asymmetry rather than to electrostatic dipole interactions. The influence of quantum fluctuations on the ground state and on the transition itself are also analyzed.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1994-12-01 | Surface Science |