Stratification-induced order--disorder phase transitions in molecularly thin confined films
- Institut fuer Theoretische Physik, Technische Universitaet Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany)
- Department of Agronomy, Keim Hall, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0915 (United States)
- Lilly Hall of Life Sciences, Purdue University, West Lafayette, Indiana 47907 (United States)
By means of grand canonical ensemble Monte Carlo simulations of a monatomic film confined between unstructured (i.e., molecularly smooth) rigidly fixed solid surfaces (i.e., walls), we investigate the mechanism of molecular stratification, i.e., the tendency of atoms to arrange themselves in layers parallel with the walls. Stratification is accompanied by a heretofore unnoticed order--disorder phase transition manifested as a maximum in density fluctuations at the transition point. The transition involves phases with different transverse packing characteristics, although the number of layers accommodated between the walls remains unchanged during the transition, which occurs periodically as the film thickens. However, with increasing thickness, an increasingly smaller proportion of the film is structurally affected by the transition. Thus, the associated maximum in density fluctuations diminishes rapidly with film thickness.
- DOE Contract Number:
- FG02-85ER60310
- OSTI ID:
- 6952759
- Journal Information:
- Journal of Chemical Physics; (United States), Vol. 101:8; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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