An example of the first is metal crystal growth from vapor, where observations of surprisingly smooth and regular crystal growth at low temperature have been made. The growth of Pt from vapor has even been observed to improve as the temperature of the crystal is lowered. This is counterintuitive since thermally activated diffusion is required for atoms to find the optimal sites in the crystal lattice. Computer simulation studies have identified several important atomic scale processes in metal crystal growth which help explain these observations. A major goal is to understand how growth conditions can optimize the quality of crystals and thin films used in various technological applications.
Amorphous materials are an example of the second category.
Computer simulations provide insight experimental studies currently cannot give into the microscopic structure and dynamics and thereby contribute to an understanding of the observed macroscopic properties of these materials. Icosahedral ordering has been found to be an important structural element in amorphous metals and other systems with near spherically symmetric atomic interactions. The correlation between structural changes and the dynamical properties such as diffusivity is being studied, in particular in relation to the glass transition. Other examples in this category of problems are interfaces between solids and liquid-solid interfaces.