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Phase Transitions of Adsorbed Dipolar Molecules Using an Extended BEG Spin-lattice Model

Document Type

Conference Paper

Journal/Book Title/Conference

Bulletin of the American Physical Society



Publication Date



The properties of dipoles adsorbed on a two dimensional surface can be modeled with the spin-1 Ising model. The extended Blume-Emery-Grifiths model (BEG) used here is the most general variation of the spin-1 Ising model. The five parameters in the Hamiltonian can be derived from specific coupling coefficients; these in effect, determine the thermodynamic properties of the system. These coupling coefficients are the inherent energies between the dipole-dipole and the dipole-substrate interactions. Initial applications in this study are CO and the halogenated methanes adsorbed on NaCl and MgO. Two methods are used to calculate the phase transitions expected for these systems; mean field and renormalization group calculations. Results from the two methods will be compared and contrasted.


Bull. Am. Phys. Soc. 44(1) Part II, 1225 (1999). American Physical Society Four Centennial Meeting, Atlanta , GA