Kinetics of Ordering for Surface Phase Transitions

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Professor Unertl and Dr. Liang, Exxon Corp., will use grazing incidence x-ray scattering, low energy election diffraction and scanning tunneling microscopy to determine the kinetics of ordering for surface phase transitions. The measurements will be compared with recent theoretical predictions about pattern formation and universal scaling behavior including; a description of domain growth, the existence of universality classes and the scaling properties of scattering functions, the description of effects of ground state degeneracy and symmetry, and the limitations imposed by surface imperfections. If validated these predictions will permit a wide range of nucleation and growth phenomena in diverse systems to be characterized simply. Technological processes including sintering in then films, solidification following laser melting, and the stability of rapidly quenched amorphous materials can be better understood. The model systems to be studied include Au(110), Pb/Cu(110), Pb/Cu(001), and Se/Ni(001). Experiments will include the use of the National Synchrotron Light Source at Brookhaven National Laboratory.