MOLECULAR-DYNAMICS STUDY OF THE SURFACE-DIFFUSION OF N-ALKANE LIKE ADSORBATES .2. ROLE OF CHAIN STIFFNESS

In the present study molecular dynamics calculations were utilized to simulate the surface diffusion of chain like adsorbates. The main goal of these calculations was to study the role of chain rigidity and its influence on the details of the surface diffusion mechanism of such adsorbates. We have found that the diffusion coefficient of both "stiff" and "floppy" adsorbates may be described by an Arrhenius expression. In addition both the activation energy for diffusion and the preexponential factor describing the diffusion coefficients of "stiff" adsorbates were larger than the corresponding quantities of "floppy" chains. The results of these calculations were compared to the available experimental data and a good qualitative agreement was found between the two.