CAPILLARY WAVES AND DIFFUSE SURFACE-LAYERS OF CLUSTERS AND DROPS

It is shown that a simple model of capillary waves excited by thermal energy yields a surface thickness about 80% as large as the total thic kness of the surface layer deduced for liquid clusters by molecular dy namics computations. Moreover, a sum over subsets of integrals over su rface harmonics is found to be a linear function of the index I of har monics up to and beyond l=10(9), thereby permitting an extrapolation o f surface thicknesses from clusters to bulk surfaces. Results imply no t only that small liquid clusters can be expected to be irregular in s hape, but more significantly that critical nuclei in phase transitions are likely to be extremely haphazard in shape rather than the idealiz ed spheres they are usually taken to be. (C) 1998 Elsevier Science B.V .