6533b85dfe1ef96bd12bf073
RESEARCH PRODUCT
Phase diagram of a model adsorbate with internal quantum states
D. Marxsubject
Quantum phase transitionPhysicsCondensed matter physicsDegrees of freedom (physics and chemistry)Surfaces and InterfacesCondensed Matter PhysicsSurfaces Coatings and FilmsAdiabatic theoremQuantum statePhase (matter)Materials ChemistryPath integral Monte CarloQuantum tunnellingPhase diagramdescription
Abstract An adsorbate in the strong binding and small corrugation limit is studied. The resulting two-dimensional fluid is treated in the adiabatic approximation: the translations of the heavy molecules are treated classically, whereas the molecular quantum degrees of freedom are modelled by interacting two state tunneling systems. The complete temperature/coverage phase diagram is obtained to a high degree of precision by a new combination of finite size scaling ideas with Path Integral Monte Carlo techniques. Even this simplified adsorbate model possesses a surprisingly complex phase diagram including first- and second-order transitions as well as tricritical and triple points. We identify gas, liquid, fluid and square lattice solid phases combined with a preferred molecular quantum state depending on temperature and coverage. Using the above methods, we determine the order of the transitions and localize the different phase boundaries to a yet unknown accuracy for quantum systems.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1992-01-01 | Surface Science |