Studies of melting, crystallization, and commensurate-incommensurate transitions in two dimensions: Third year progress report
The free expansion melting of a 2D suspension of micron-size polystyrene spheres contained between parallel silica plates has been analyzed in some detail. The translational and orientational correlation functions conform with KTHNY theory prediction of a two-step melting process. The visual observations and study of the defect structures and evolution strongly suggest the process is first order with two-phase coexistence taking the place of the intermediate (hexatic) phase. On the other hand, melting of a 2.88 ..mu..m monolayer on water is in accord with KTHNY including the observation of dislocation-pair unbinding at the first transition. However, there is no evidence of the dissociation of dislocation into free disclinations at the second transition (the defect structure is much too complex here). Dynamic light scattering experiments on a 2D crystal on the surface of water yield viscous damping factors, force constants and the Lame coefficients. 2D computer simulation, reveal cooperative motion along chains of particles (''snakes''). They appear to be the principal cause of diffusion near the melting point and important in the melting process. 36 refs., 17 figs.
- Research Organization:
- Colorado Univ., Boulder (USA). Dept. of Physics
- DOE Contract Number:
- FG02-86ER45236
- OSTI ID:
- 6592895
- Report Number(s):
- DOE/ER/45236-T1; ON: DE89005907
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360602* -- Other Materials-- Structure & Phase Studies
BURGERS VECTOR
CORRELATIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALLIZATION
DISLOCATIONS
DOCUMENT TYPES
HYDROGEN COMPOUNDS
INTERSTITIALS
KINETICS
LAYERS
LINE DEFECTS
MATERIALS
MELTING
MICROSPHERES
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHASE TRANSFORMATIONS
PLASTICS
POINT DEFECTS
POLYMERS
POLYOLEFINS
POLYSTYRENE
POLYVINYLS
PROGRESS REPORT
SYNTHETIC MATERIALS
VACANCIES
WATER