Particle growth INDEX

Figure 7.2 The relation between the particle growth in the disk mid-plane traced by the millimeter opacity index and that of the inner disk surface traced by the 9.7 pm silicate emission feature. The star symbols represent individual disks. Data points are from van Boekel etal. (2003), Natta etal. (2004),Furlanc/ al. (2006), Rodmann et al. (2006), and Lommen el al. (2007). Typical errors are 10-30% in both /3 and silicate band strength. Note also that differences in how the silicate band strengths were derived may introduce slight systematic offsets for the different data sets. The circle symbols represent dust opacity models calculated for the interstellar medium at a range of densities. From top to bottom the circles are Ry = 3.1 and Ry = 5.5 from Weingartner Draine (2001), a Spitzer-constrained dust opacity for dense clouds from Pontoppidan et al. (in preparation) and the particle growth simulation for protostellar envelopes [thin ice mantles, Ossenkopf Henning (1994)].

Several strategies were appUed to produce samples for TEM and kinetic studies [8, 21], but only one route is presented here (Fig. 15.3). Noble metal nanoparticles were grown via metal evaporation on a crystalline soluble substrate (e.g., NaCl(OOl)), leading to an epitaxial growth of particles with regular shape and well-developed low-Miller index facets (Fig. 15.3). Thereafter, the metal particles were embedded in a thin (25 nm) amorphous oxide fdm, before the metal-oxide system was lifted off the substrate via flotation in water [8, 18, 20, 31]. 

As a consequence of phase separation particles or domains of very small size and different refraction index appear. When they are big enough they become light scatterers and the mixture becomes cloudy in the visible range. But the size of domains plays with the wavelenght, so IR radiation can also be used to determine the onset of phase separation and characterize the growth of the nascent structures. 

---